Hello....I Finished My Periods About 4 Years Ago Now,but This

Hello....I finished my periods about 4 years ago now,but this morning there was some very thin,light pink vaginal blood...Don't know if this could be connected to eating a lot of beetroot last night, or some light sexual activity,which hasnt happened for a couple of years now?? !! I had a polyp removed from the uterus about 4 years ago now,and results were fine..?? Should I see if it clears up with no beetroot,or see the gynae asap..?!"