Souttar is to miss the rest of the season due to his horror injury and has had to take injections in his stomach as he battles back to full fitness.
However, the 20-year-old remains in high spirits and has spoken for the first time since he left the Celtic Park pitch on a stretcher.
“I remember jumping to challenge for a header, but as I raised my calf off the ground I felt my Achilles pop and split apart,” Souttar said in an interview with The Sun.
“I felt it move up the back of my leg and it was a horrible feeling.
“I tried to take a few steps – three in total, having watched it back – but there was just nothing in my leg. It was agony when I hit the turf.
“When the stretcher came it was all a bit of a blur. I was telling myself everything would be fine, but in the physio’s room they said they could feel a gap where my Achilles was meant to be.
“They knew straight away that it was ruptured, so there was no point in even going to the hospital to be told the same thing.
“The manager sat with me for five minutes after the game. He was brilliant, as were the other lads, and I could tell they were all gutted for me.
“I travelled home on the bus and I was probably in denial that night, hoping for the best but I got a dose of reality the next day. We went to the hospital, they confirmed everything and said that the best-case scenario would still keep me out for at least six months.
“All I knew about the injury was that it happened to David Beckham a few years ago, but it’s one of those that’s up there with cruciate ligament damage.
“It hits you when you hear it. I’m trying to take every day as it comes. If I dwell on how long I could be out for then all that will do is put more stress on a body that’s already suffered enough!
“At the moment I can barely do any rehab, other than some very occasional light mobility work. I’ve been doing some upper-body work in the gym with Callum Paterson, who picked up his cruciate ligament injury three weeks before mine.
“Subconsciously it’s probably helped both of us to have someone else in the same position, although with his injury he was able to get back on the bike pretty much as soon as he’d had his surgery.
Souttar has been left housebound by the injury and thanked his girlfriend and family for looking after him.
“I can’t even go to the games,” he said. “I went to the win over Rangers but that was before my operation in London, because I can’t sit in the one position for too long or negotiate that many stairs.
“I can’t do the things I’d take for granted like jump out of bed, make a cup of tea or take my dog, Lola, for a walk.
“I was in a cast for the first two weeks and every hour I had to have my feet in an elevated position for 50 minutes. On top of that, I had to inject myself every day in the stomach to cut down the risk of a blood clot.
“It’s fair to say I’m better with needles now than I was.
“My mum, gran and pals have all been up. I live with my girlfriend, Kayley, and she, especially, has been great. I can’t sit still at the best of times so I’ve probably been a nightmare for them all.”