Repetitive, intense pain in belly button area

Over the past 3-5 months, maybe less, at random intervals I will experience terrible stomach pains, as in it feels like my stomach is digesting itself, me moaning on the floor on the verge of tears pain. It starts very suddenly; no gradual anything. One minute I'll be fine, and then suddenly I'm extremely nauseous. I race to the bathroom, my stomach churning, but I can't throw up. I'll gag and retch, but nothing comes out, even if I've just eaten a meal. I've even tried inducing vomiting by shoving fingers down my throat, which worked about twice and now I don't have a gag reflex, so it literally feels impossible for me to throw up. After I fail at vomiting, the pain starts. I don't know how to describe it. Maybe like cramps? All I know is, it's intense, incapacitating and terrible, and can last 2 or more hours, during which I will alternate between heavy nausea, attempts to vomit, and pain. As I said it's my entire stomach area that hurts, like belly button area, stopping below my abs, ending above my lower abdomen. The attacks are pretty spread apart, but I've been having a lot recently, which makes no sense and isn't normal for me. I don't know of any specific triggers; it's not like it only happens when I eat a certain food, or if I'm stressed or something. It just....happens. Anyways if anyone could tell me what might be going on, I'd be very grateful, as this a painful and horrible event which has kept me awake at night and had me have to cancel plans. Also, if it helps, I'm 17, a girl, and have no diagnosed anything or past medical issues regarding my stomach. Thanks for reading!