implantation or beginning of period?

Melissa
So I thought I would check my CM last night and found light brown mixed with milky CM, I didn't think anything of it. But when I went pee this morning I noticed either small clots or parts of tissue and a little blood. Is this implantation or beginning of period? They say implantation causes mild cramps but I had bad cramps from 7:30-11am this morning. And TMI but I had brown AND red blood on my tampon. Help me please :(