what's happening?

I had rough sex with my BF and the following occurred. 
-After the sex I had brown stuff coming out and also pink mucus coming out of my flower
-super sore
-itching/irritated
-the discharge is super watery
-it was more normal yesterday but I had some spotting today
-slight cramping 
 
Also to add I had protected sex 8 days ago could this be implantation bleeding?
Anyone experience this before?