extreme pain on my period?

so when i get my period i get this horrible pain. it literally feels like my uterus or a body organ is falling out. it happens when i use the bathroom or sometimes when i’m just standing and it’s horrible. i don’t know how else to explain it other than feeling like some body organ is literally falling out. it’s not cramps or anything. this usually happens on the 1-2nd day of my period but only then. it doesn’t happen any other time. i feel like my periods are pretty normal other than that pain. does anybody else feel that way? is there something wrong with me?