MP Fiona's O'Donnell's diary

After April's deselection of East Lothian MP Anne Moffat, Fiona – a 50-year-old charity volunteer, behind-the-scenes Labour Party worker and divorced mother of four – was selected as the Labour candidate for East Lothian seat.

Fiona, who lives in Liberton, won the seat and is now one of Westminster's record number of 232 new MPs.

Here, her diary reveals an emotional and often funny journey of discovery involving mice, Gary Barlow, pyjamas, and even some politics.

WEEK ONE

It's six years since my youngest boys left home to continue their studies. Back then I worked for a children's charity and thought I'd spend the rest of my days simply waiting for visits from my children – I suspected they'd draw up a rota for visits.

That changed the day before the General Election was called and I was selected as the Labour candidate for East Lothian. I'd worked for the Labour Party in many campaigns over the past few years, but nothing prepared me for the experience of being a candidate – or now, being a Member of Parliament.

It's Tuesday 11 May and I travel to London by train, standard class, with former city councillor Ian Murray, now 'newbie' MP for Edinburgh South. Neither of us can stop smiling.

The smile is wiped off our faces at our hotel: the rooms are up ten flights of stairs and the lift wasn't working. Later I unpack and have my first crisis moment as an MP: I haven't packed enough pyjamas. Note to self – MP means More Pyjamas!

Next, the Westminster induction tour. I gaze at the tiles in the main lobby and am struck at how the patterns have faded. I think of how many have gone before us and of the history of this place.

Some awful things had happened here, laws passed that consigned many to lives of poverty and disadvantage, others that criminalised people because they were different, but I feel optimistic when I think of radical legislation – the National Minimum Wage, Civil Partnerships and the right for gay couples to adopt.

How encouraging to think somewhere so steeped in tradition and history could also set the agenda for real change.

How amazing it feels to be a part of it, even if my 'office' is a hot desk shared with the other Labour 'newbies'.

After a night of disturbing dreams, the like of which I haven't known since first day at secondary school, Wednesday begins with a briefing in the Chamber of the House of Commons and for the first time we sit on those famous green benches.

I fight back tears. I think of the people I couldn't share this with, like my late mum and dad who encouraged my brothers and I to believe there was nothing we couldn't achieve and that we should never be intimidated by wealth or power. Here endeth the gospel according to Pat and Gladys Kenny, my beloved mother and father.

It's a short week, and by Friday I'm back in East Lothian. Again, it's emotional as I'm reunited with people who worked so hard during the election campaign. I realise how I've missed them.

Later I have my first home visit to a constituent and already I see I can make a difference for them. This is the real opportunity of being an MP – shifting the balance of power to give fairness and justice.

Come the weekend, I feel guilty for having some 'me' time. I figure out how to access e-mails from home and keep checking in. Then I remember my most urgent business – the need for more pyjamas. I hit the shops.

WEEK TWO

I feel confident enough to travel without Ian! I couldn't have got through that first week without him. We had a lot of laughs but we also put in a lot of hours, working late into the night. I doze off as the train leaves York then wake in a panic as we pull into Peterborough. Is Peterborough north or south of London? As a student travelling from home in Fort William to Glasgow I'd have to ask three people if I was on the right train before I could relax. Will I ever be as blas about all of this?

Monday evening and I meet up with two of my sons who live down here. It's nice to think I have finally done something to make them proud after all the happiness and pride they have brought me.

On Tuesday I head for a briefing on MPs' Register of Interests, not because I have anything to register, but because I don't have a clue where to find forms that I need.

What an education! One MP is asking about transferring shares into his wife's name and whether he needs to declare all his homes if he spends some time each year living in them. Then are many questions about ownership of land, company directorships and former clients. I feel so out of place and different.

When I get to ask about where to find the form I need, it turns out that I have a post bag at the Post Office – news to me. I head off to pick up my mail for the first time. I have to make two journeys to carry it to my office.

Tuesday also sees the first business in the Chamber, the election of the Speaker. It's strange to be close up to people I've only ever seen on TV. Sometimes I recognise a face but can't place the name, others I do a double-take because I thought the person in front of me was actually dead!

The people in front of me are rude and noisy. I'd like to reprimand them, but apparently this is acceptable behaviour. Some of the comments are cruel and downright discriminatory.

There's a moose loose aboot this hoose! Alarming news that mice are often to be seen running around the Houses of Parliament. I spend the rest of the day thinking I feel something touch my leg and wildly overreact. I sit with my legs tucked under me.

Thursday and it's my day to be sworn in. The Speaker sits up high in his chair and the MPs line up in front of him, waiting to be spoken to. It's a bit like Christmas and they're children queuing up to see Santa.

I feel emotional again – hope I'm not the first one to cry when it's my turn this afternoon.

Suddenly I hear music. Take That. There's a moment of horror as I realise I haven't switched my phone to silent. I scramble around in my handbag. The chamber microphone has picked up the sound and it resounds around the chamber.

I had meant to change the ringtone after Gary Barlow came out in support of the Tories. Well congratulations Gary – you have now played Hampden and the House of Commons.

These have been the most incredible few weeks of my life.

Until now I always felt something of a disappointment. Charles Kennedy and I went to school and university together and were both expected to have political careers. Charles did. I, however, had four children.

Not that I ever regret my choices. After all, it's probably better to be an MP for the first time at 50, than a parent for the first time at the same age.

So maybe I did get it right after all...