I have a problem and I don’t know what to do

I have been prescribed monistat 3, the vaginal suppository cream. My problem is, and it’s embarrassing, that I can’t insert the suppository into my vagina. I’ve never been able to use tampons, either. I’ve tried so many things, nothing works. I try to push it in and it just hurts terribly. I know I may have to talk to my doctor about it, but I’m incredibly shy and I might get too nervous. I’m 17, and I’ve been the the gyno one time, and she didn’t do a physical exam. Can anyone give me any kind of advice??