One tiny spotting at 30 weeks

Last night while wiping i noticed a very small rusted spot of blood on my paper. I am not even sure if it came from vagina or from the hand coz i saw it only saw it while turning the paper while disposing. Ever since i had been little nervous baby is active as usual and no other signs. I have my regular ob appointment with scan on this Saturday 2 more days. I have been monitoring now for a day and I can’t see anymore of it. Please advice me if i should run right-away to er or just monitor ? Is this common at this phase? Any insight would be helpful. Thanks