Pelvic pain on and off, one sided?

I keep having on and off pelvic sharp pain on my right side. Im scared something might be wrong with my baby. Ive been having it since when i had implantation bleeding and still having it. Yesterday I was also slightly bleeding light orange to light brown discharge whenever i get constipated and do bowel movements. But today, its dark to light brown and have little stains on my undie. What could be wrong? Im 8 weeks. Could it be a miscarriage? Im so scared... no ecoptic pregnancy.