I've got lots of blooms that fall off then I get more blooms but no pumpkins. I 've seen lots of bees.
I'm sorry your pumpkins aren't producing for you!
Stress, a calcium deficiency, even lack of pollination (even though you have seen bees) could all be contributing factors to your pumpkin blooms falling off.
There are handful of things you can do to remedy all of these. This article may help you: