ADVICE PLEASE: I don't think I know the difference between a period and spotting. See, I know if it…

ADVICE PLEASE: I don't think I know the difference between a period and spotting. See, I know if it continues past 5pm, it's your period and mine has but it is sooo light! I only am seeing the blood when I wipe. Never had a had a period like this but if it was spotting, wouldn't it not last this long?