This whole month I've been having problems with using the restroom such as constipation. When my period came it was spotting, then heavy, then spotting again. It also came with diarrhea. I've noticed that some of my feces being black which I looked up to be internal bleeding. I've taken medicine but that didn't work, I'm also bloating and feeling much nausea. I don't think it's pregnancy ( period came with tissue ) but these are very concerning, could this be serious?