I'm not supposed to start my period for 4 days and I started today after feeling terrible cramps. I have a very regular period but am worried it's implantation bleeding. When I noticed I felt stuff come out I went to the bathroom and there was white discharge with some blood in it and drops of blood fell in the toilet. I'm still having terrible cramps even though not much blood is coming out. Is this my period or IB? I've had a lot of sex at the end of May but not much this month.