I Am An 18 Year Old Female. Four Days Ago

I am an 18 year old female. Four days ago on Friday, I woke up to bad constant pain right below my belly button. The pain was bad enough to make me cry. I felt weak and dizzy and when I tried standing for a few minutes, I felt like I would collapse and black out. Sitting in a bed and not moving helped. When I pressed my hand right where it hurt, it hurt worse. When I tried to poop, it hurt so bad that I had to stop. This lasted about an hour and I took some Ibuprofen and it went away. Now, 4 days later the pain has come back right below my belly button. It isn't near as bad and it's tolerable. I'm not dizzy like I was before and I can still go to the bathroom, but I'm still wondering what is causing the pain and if I should be concerned.