period issues

first of all lets start with I am not nor was I ever pregnant. Jan 12 i started my period it was very light and not at all like my usual periods i had a few days of "regular" flow but most of the time i could go a whole day with one pad and not worry about leaks or needing another pad. this kept on untill about Feb 15 when it stopped all together. (this was the second time it lasted over 2 weeks) yesterday (feb 26) my period started again and with a vengence! today i bled through (and i mean through.. im just glad i was wearing black pants) an overnight pad in 3 hours i have been crampy and i had really bad gad and bm's. any ideas on what could be going on? should i be worried? ****edit - put a new pad on at about 1130pm woke up at 5am to pee changed the pad and then at 730 had to change it again. 730 - 1100 pad change then 11-6 soaked through (didnt have enough atvwork with me to change) currently on pad 4 since 730 this morning*