Bonding with unborn baby

I have pretty severe depression and ptsd from before getting pregnant, I’m about 5 months now and we just found out our son has health risks and we need to go through extensive testing to see what’s going on. I used to be super bonding with him but I feel like since finding out I don’t have the same strong bond and I feel like a terrible mom for not being the same. I have lots of history with loss within my immediate family so I’m not sure if that’s why I’m pulling away, but is there anything I can do to help rebuild the bond?