TMI!!

I'm so sorry for the tmi but I'm so scared as to what this might be. it didn't give me the option to click tmi, so please no negative comments. I've had spotting like this since Sunday (about 5 days) off and on, some spotting was pink, some light brown, some dark, but this is the heaviest it's been. this has never happened to me before (brown/ pink spotting of any kind) and it seems really thick to even be spotting. someone please let me know what it could be. my period was supposed to come on the 14th so it's 11 days late.