I've been dealing with something very similar. I was officially diagnosed six months ago, though I had it longer. Therapy and most likely taking medication will help, at least it does with most people. When it comes to the therapy, make sure that your therapist is a trauma therapist. When it comes to the medication make sure to out way the pros and cons and have an open mind. Other than that, you'll hopefully be taught techniques that will help with the side-effects of PTSD (depression, anxiety, hypervigilance, dissociation etc.). This is a lot to take on at eighteen. I have an idea how this feels because I'm only two years older than you but I've gotten better at managing everything through time, patience and practice. I still have extremely difficult times, like right now (I'm hallucinating and the guy is in my doorway right now but I know it isn't real). I've had constant flashbacks today along with not knowing where I am. I used to spend every day this way, now I don't; though it is still frequent. You learn to manage the symptoms and stay in control of yourself, unfortunately it's a hard fight that really doesn't end but it does get manageable. You'll learn what works for you and implement that. You'll get through this and you'll be able to help someone else who's in the same position you are now. Try prazosin for the nightmares (ask your doc). I also got a therapy dog to help out with the panic attacks and such; he really helps. Message me if you ever need to talk or just post. I'm on here a lot, I'll usually see it.