I suspect you are correct. My condolences. This can be a vexing problem, although you identified it fairly early, which is good.
Could be.
Could be that, too.
Let's try a few things to see if they help. Don't squat for the next four days. Take a loading dose of ibuprofen (800 mg three times a day for four days). That is four 200 mg tablets at a time. Take it with food. See if that knocks down the pain and inflammation a bit. Cease the big dose of ibuprofen after that. I have a couple of ideas for how to train the squat after that using some eccentric work. Do you have a pain free range of motion, or does the tendon hurt pretty early into your descent?