I am not in your position so from the other side I truly believe it is grief.
Grief for what "should have been", "grief that your hormones on and body don't get to the thing they exist for", "grief for a longer term future I'n not going to have".
Grief doesn't have a set pattern, what is ok today is unbearable tomorrow. It will hopefully diminish in intensity over time but I suspect like with all grief there are still twinges of sadness.
My analogy is with my parents (I belong on the Stately Homes!) it isn't grief for losing them (still here and not part of my life) but over the decades I have grieved for what I never had and never will have. At times it hurts as much as losing close friends, occasionally something happens and it roars up and slaps me around the head again. The endless conversations from other people about their Mum's still really hurts sometimes- it is a bit like a club I've never belonged to... oh and the judgement too 

I've been friends with people whilst going through long term infertility and even as a teenager I could see how f*cking heart breaking it was and raw and just exhausting. No I am old I have peers that have had to come to terms and move on and they are less painful place but are still deeply hurt at times by utterly inappropriate comments etc usually from family tbh.
Op find a good therapist, literally phone a few up and chat and see who you click with. Find a forum or thread where you can rant and rave with people that understand,
For those with the bingo cards on here:
Never getting pregnant - fucking painful
Never giving birth - fucking painful
Never being parent - fucking painful
Never being a grandparent- fucking painful
EACH is painful and sad in their own right. I will be sad if I don't become a grandparent, obviously I always tell my DC I want them to be happy and life will be what it is (2 of my DDs gave gynae issues) but I will be upset and grieve for what "I wish would be" for me as well as a separate grief for them if they want parenthood and it doesn't happen.
Op be kind to yourself and perhaps if you feel brave enough do make comments to others so they know you are not childless by choice 




