Spotting or early period?

So this week is my ovulation week, and yesterday was my peak day. I'm not supposed to start my period until the 21st of this month. This morning I went to the bathroom and I'm bleeding. It isn't enough that it made a mess, but it was enough that I had to put a tampon in. I'm also having cramping. The color of it was a bright red, and normally my periods are more dark red to brownish. My boyfriend and I did have sex yesterday and we're planning to today as well, but now I'm not sure if we should. Does anyone have any idea what might be going on? I've never experienced this before and my periods always come at the same time every month.