Everything "cums" back out

Hi everyone. This is definitely TMI but I need help.

Whenever my husband and I are in bed, when we try to do it, once he is done, everything comes right back out of me. We have been trying to conceive since November 2018 now and I'm getting depressed. I think the fact that nothing stays in me is playing a key role as to why we are not pregnant yet. We have tried all positions and it doesn't seem to help.

Does this happen to everyone else? Am I doing something wrong?

Can someone help?