I think I'm ill and Doctors won't help?

Hannah
I figured I'd use <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a> for some advice because doctors won't take me seriously. For a couple years now I've gotten severe and nearly unbearable sharp stumach pains and recently in my bladder area aswell. They are random, and last only about 10 seconds each, but feel like someone is stabbing me in that area. They are so painful sometimes I have to sit and they bring me to tears. I was tested for a UTI and I don't have one, but they never test me for anything else. They just give me nausea pills and ask me to leave. I'm only 16 so I definitely shouldn't be feeling like this. What do you think this is? What kind of tests do you recommend? Has anyone else experienced this? I need advice, big time.