Implantation bleeding could I be pregnant!!!

I had sex May 11/12 & I’m 2-3 days late on my period I should had started my period the 27th today On the 27/28 I had white creamy discharge now on the 29th which is today I thought I started my period I saw a light red blood on toilet paper when I whip myself it wasn’t no blood in my urine but each time I went in the bathroom it somehow went away it look like it was mix in with white discharge at first but now when I whip myself I don’t see it anymore I don’t have no idea what’s going on I have lower back pain and my stomach feels like I’m about to start my period but I haven’t