Give some insight maybe?

Br

I don’t know if this is seman or discharge... my bf and I have had a lot of sex. I’m supposed to start my period Saturday but haven’t had a positive OPK this cycle. Aaannnddddd I’m not sure why there’s blood in it?? I went to the bathroom and when I stood up to wipe, this big long, thick blob was hanging out of me... help?