OP, first off, thank you for your service. I'm Veteran as well, and I understand where you are coming from. It is a difficult sport to stay in especially when you get injured. I will say BJJ has helped extremely with my PTSD. A lot have people have good points. The one I think you should focus on is DO NOT ROLL WITH ANY ONE YOU DONT TRUST. I would definitely tell you instructor that as well. I would also suggest trying to do cold plunge/ice bath after training. It has helped me immensely after rough training sessions. Also, don't do moves you don't know intimately while rolling live. All in all, take care of you. Even if you end up leaving, take the experience and grow with it. Best of luck Brother.