A lot of the other posters have given some great advice from a technical perspective. I'd suggest taking some time to evaluate and improve your mental health as well. If you're putting yourself under so much pressure, that pressure alone will hold you back to a great extent.
First off, just relax. Take a little time off to reset your psyche, overcome your burnout, and rediscover your confidence/interest. It's amazing what taking a week off can do.
Take up some activities that have been shown to help with stress relief. Meditation. Exercise. Long walks. Digital disconnects. Healthy sleep cycle.
Read this book: The Inner Game of Tennis. It's a short read, but it will transform the way you approach high-pressure situations.
You mentioned PTSD - do you actually have PTSD, anxiety, or other similar mental health problems? If so, talk to a counselor or find some way to address those underlying issues.
You have a long career window ahead of you, so don't burn yourself out at this point. Job prospects are great for CS majors, and you seem like a guy who's very motivated and hard working. Spend a bit of time taking care of yourself, and I'm sure you'll be fine in the long haul.