Interesting story. PTSD is a diagnosis and often comes with anxiety. I've got them both and have also been diagnosed with a depression disorder.... I think the stuff you worry about is directly linked to the loss of your leg.... I personally think your therapist has the thing nailed down tight.
What I suggest is, during therapy sessions, take notes. It took a while for my therapist to actually make any sense to me, but when she did it completely validated all of my thoughts, worries, and fears.
My therapist was trying to attach a lot of what I was going through to my past, and I just wasn't having any of it. Being a man, (hard headed to boot) I thought that I had dealt with all of that garbage and put it aside to move forward. The fact of the matter is, I never did deal, I never did grieve over things because I saw them as weaknesses and the last thing I ever wanted to be was weak. When all of this finally sank in, instant relief. All of the crap in my head now had a name, it had an origin, and it now had a starting place to start actually putting this stuff behind me.
Stick with it man. Give this therapist a shot and open up... not only to the therapist but to what he/she is saying... take those notes, look back on them. You'll get this figured out!
Good luck, and keep this thread updated.
do you take pills for this? if your having reoccuring nightmares i would see a doctor again