I'm so sorry for your losses.
I know how you are feeling and I think yo are completely normal in grieving your babies. I still think of my angels and what might have been especially on due dates and other dates that are significant to me. I don't really cry much anymore, but I still remember.
I can also relate to the fact that DH's don't really understand a loss. Although my DH was sad at our losses, I don't he ever really understood how I felt until one day in the middle of the night after our second mc, he came upon me in what would have been our babys' room sobbing with my bubbas ultrasounds around me and holding onto a blanket I had brought him. Even now remembering it makes me teary.
You are entiled to feel sad and there is no time limit to your grief. It will be difficult for you since your friends are having bubs too. I also had this after my 2nd mc. It is hard to celebrate when you're thinking it should be you too. Take time out and be sensitive to yourself. Maybe spoil yourself a little.