Why do I cry so much

I think at the moment it's partly cause I'm on birth control and partly cause I'm under a lot of stress but even when I wasn't on bc or under stress I'd cry easily if I got frustrated with class work or if someone yelled at me, ya know small stuff with simple solutions. When I was little I'd even cry in the nurses office in school tryna explain I twisted my ankle or had a sore throat -and not even cause it was painful, lil 10 y/o me would be thinking "why tf can't I stop crying? She can't understand me asking for an ice pack through my sobbing". It's annoying to me and I can't control it. Wtf is wrong with me?