Help! What's wrong with me?

I wake up this morning with cramps, backache, and when I go to the toilet, wipe, has a slightly pink spotting on the tissue and now become light bleeding with mucus. I am on cd15 today. Af due 11 more days. Never like this before. Never has mid cycle bleeding. And also according to Glow my O day was on cd12. Is this implantation bleeding? I think it's too early but what is this spotting and bleeding?? Anyone happens like this before?