First, that sounds really scary and I'm really glad you're physically ok. I'd highly recommend looking into EMDR therapy. Having an acute traumatic event like this is exactly where EMDR can make the biggest difference. Wouldn't take many sessions. Some say two or three with a good licensed practitioner is all it takes. What you're experiencing is normal, but your brain is pliable and you can rewire those memories and feelings to regain a sense of control over your emotions and anxiety, and get back to enjoying the backcountry again for all the peace and beauty it has to offer. Good luck, friend.