Why can't I wear a tampon?

I've had my period since I was 9, and I used to wear tampons while swimming from 9-13. When I was 13, I had a serious episode during my period. The cramps were so bad that I could walk and I threw up and fainted at the same time. It was really bad and the worst experience in my life. That was 6 years ago and ever since then I haven't been to put a tampon in. At first it worried me only a little and I just avoided swimming on the first day, but now it worries me because I found that a lot of the symptoms for dysmenorrhea are what I get during my periods. And also, I'm quickly getting to that age where I might start a family and I'm not even sure if anything will go in! I've tried all the tricks to help muscles relax and all of the ways the box and online tells me to put a tampon in and it's just not happening. What happens when I try with the applicator, is that it gets to a certain point where the applicator goes back on itself and it just won't go any farther. Is there something wrong with me or what? I really want to be able to have at least one child after all of this trouble I went through with this thing!