whats up with my AF...TMI

okay so i was late on my period by a week 3 days ago i started out of no where i had no cramping the day b4 no spotting nothing then i just started bleeding really heavy with alot of clots bigger clots and i was in the worst mood i couldnt shake this feeling i was sooo pale and my head hurt and i was cramping so bad it went around to my back to where if i turned it would take my breath so i was like man this period is going to b horrible and i went to work lastnight and was busy so i headed to the bathroom to make sure i hadnt bleed thru and it was nothing at all i slept all night with no tampon or panty liner and i woke up this morning wiped it was pink and then nothing now so i only had a heavy heavy period for 1 day what the heck is up with that anybody else ever have this? im 31 and this is a 1st for me