what in the hell is going on with me?

ol

so i’m on birth control and I took a pregnancy test and i️t came back negative. I keep having brown discharge and it’s been happening for about 2 weeks now. i️t started happening right after my last period. also, my stomach has been gurgling constantly! i’ve been on birth control for about 3-4 months now. someone please help me. should I go to the doctor?