I'm terrified to orgasm...

I've been trying for years to orgasm, but I always stop before I reach it. I don't know why, but it seems too intense for me and I sometimes find myself physically kicking to try to get away from the feeling. I'm a virgin and I've never had any sexual relations with anyone other than myself, but I think this might be a mental thing. I don't know why I just stop! I know it is going to feel good, because it's a universal fact that orgasming feels good, but I just can't do it!!

Does anyone have any tips on how I could achieve the big O? How can I calm myself enough to let myself have one? Anything helps!

Thank you!

-Alaina