PTSD, Depression and Jealousy

I have been struggling with ptsd for three years now with off and on symptoms(I was sexually assaulted and acquired the condition). I have been specifically dealing with depression for about 8 months and I don’t know why because I have so many good things going on in my life and I have plans and a great future ahead.

I also am deeply struggling with jealousy of my fiancé’s best friend because she is pregnant (it happened by accident but now she’s excited) and she has asked him and I to be the godparents. This makes me so happy because I will have a goddaughter, but I am still overwhelmingly sad and jealous that I do not have a child of my own at the moment. I’m 22 and in my first of three degrees that I need for my career and this is huge to me that I complete these before starting a family because I want to be able to devote all my time to it for a while. I also know I will most likely struggle with conceiving because of my families medical history and my own medical issues. I want to just be happy for her but since the moment I found out in September I have struggled with jealousy and wanting to have my own baby so I can be a better mother first and be the one she goes to for advice. But I’m saddened that this isn’t my situation and that I’m stuck in this place. My fiancé tries to understand but doesn’t fully understand how crucial this is to my life.

Please help me cope with this better.