HELP 4WEEK PERIOD..

in june, i went to a party and was possibly date raped. not going into details, but i came home in different clothes and no undies. its now august 14th and have had my period for almost 4 1/2 weeks. i have gained a little weight, and have recently felt sore "downthere". Normally my periods are completely normal, 5-7 days regular blood, cramps the first 2-3 days, and now its no cramps, and thick dark red clots, or brownish thick almost gritty discharge. i have had a few headaches and nausea.