i haven't talked to a doctor about it or anything, and i'm not sure if these are even symptoms of it or something else?

when i'm about to start my period i usually get really sharp pains/cramps but they're not in my stomach, they're mostly like in my actual vagina...like around where a guy would enter. and i noticed when these cramps come is when blood is coming out. also i have muscle aches in my back upper thigh like right under my butt and those aches get worse when my period is about to come. usually i don't really notice them but when i'm about to get my period they're a lot worse. i don't get my period regularly since i'm on the depo shot but when i do these cramps are INSANE and i feel like it might be endo?