What Causes Abnormal Menstrual Discharge?

I ve been on my period for 1 weeks and 2 days. The first day I had just stained my underwear but didn t pee blood that day or the next but when there was blood on the toilet paper . until 2 or 3 days later I actually peed blood but then again it stopped peeing blood , 2 days ago I showered and blood just came out and it didn t look like blood it looked like a light red color