Salam! Spotting tu memang boleh jadi confusing, but since your period is usually regular dan last period was the 13th, better you go see your doctor or clinic to check properly, okay? They can do a proper exam and rule out anything else, bukan just rely on UPT je. A few of my mum friends pun pernah experience spotting for different reasons, so it's worth getting checked out to be sure. Jangan worry, usually nothing serious, tapi best to get peace of mind!