My tummy hurts, I see something like a heartbeat under my belly button…

My tummy hurts, I see something like a heartbeat under my belly button. My belly button is also sore and my breasts are sore. I went to the clinic and was tested negative. My tummy is getting bigger and I see my period every month. On May 21st to 24th, I had yellow discharge and on the 26th to 28th, I saw some small blood. Usually, I see it on the tissue when I poop four days later. I felt like I was going to pee but when I go there, it comes out small. Since yesterday, I've been going okay. I don't know what's wrong. I have abdominal pains and back pains, and my left