Secondary infertility brings with it a very complex emotional roller coaster. That feeling of “am I wrong for feeling this pain when so many people don’t have any kids and would give anything for the Brachos that I already have” is very normal. It is also very legitimate and normal to feel that pain. The advise to check out some forums specifically dedicated to this topic is a good one. But you most certainly are not alone.
If you are the type to get chizuk from fiction, Sara Weiderblank’s most recent serial in Binah featured a beautiful and realistic portrayal of someone dealing with secondary infertility. Maybe you can get the back issues from someone.
Hatzlacha to you in this nisayon.