3 days late for my period, once i got it, it was all brown spotting. lasted 5 days. my period is always very heavy. could this mean i am pregnant?

Late periods: It depends on how old you are or if you have had intercourse within the "danger" period, but yes missed periods for females almost always warrant a pregnancy test. Spotting can also mean hormonal changes which may be natural as you age, or related to a number of other factors, including stress, nutritional variation, anemia, etc. Recommend you visit an MD clinic to be checked out.