Well the panic disorder seems like it's almost part of PTSD... having panic attacks is what defines Panic Disorder, so it seems like it's almost implied with PTSD since as far as I know PTSD implies that you have panic attacks in certain situations. And they are probably tacking on agoraphobia since (as you say in your post) you don't really leave the house much (I don't leave the house much either!).

I think the other two diagnoses are just extensions of your PTSD - you just need to focus on getting better PTSD-wise and the other two problems will follow since they are just extensions of the PTSD. Don't let the additional diagnoses bring you down at all and make you feel like it's any harder to overcome - they are just "add-on diagnoses" that are describing your symptoms of PTSD I think.