I had my period oct 19. normally have a usual 28-30 day cycle. tan spotting 3-5 days before expected period. implantation or early period?

Yes: It could be either. Any time you are having unprotected intercourse, pregnancy is a possibility but things as simple as the time change, stress, changes in diet or exercise, and medications taken for other things can disrupt your cycle. When in doubt, do a pregnancy test and if you don't have your period and it is negative, repeat it in 3days to 1 week. Best wishes. Hope this helps.