For The Pass Few Months When I Get My Period

For the pass few months when I get my period it stays for over two weeks once it stayed for almost a whole month. It's very heavy and I have a lot of blood clots. I can feel then coming out when I stand up or go to the bathroom. At one point I got up one morning and it was so heavy it came threw the pad and my clothes and was all over the floor. I have to change my pad sometimes every 30 mins and I'm nervous to leave the house when I have it. I never had this problem before. Why is this happening?