What Causes Irregular Heavy Flow Along With Headaches?

hi I am just wondering if there is something wrong, i had what i thought was a really heavy period that ended 2 weeks ago, and out of the blue today it happened again, I went to the toilet and there was blood everywhere and it seems to keep coming. I stood up and found that there was blood on the bathroom floor and on my foot, I have used a full packet of sanitary towels since about 7pm and have had to change underwear and trousers twice. My head has been throbbing all day as well and painkillers have not helped, is this normal?