period

Okay so, I've had periods for a while now and I always use pads, I know they are messy and shit but whenever I try to use a tampon I can't! Like it won't go in, and I've gone by instructions and it just hurts, And feels weird and won't go in, I don't know if this is because it's dry or not (because honestly with constant blood coming out you would think it's wet) but it just doesn't work, anyone else had this problem or is something seriously wrong with me.