please help!

So I had my period last month July 18 thru the 22 I had unprotected sex on the 22. I started ovulating on the 29 of July though August the 2 according to my app. I had unprotected sex on the 31 of July and again on the 1 of August. I've been having this light pink spotting and brown distcharge enough to wear a light panty liner since about the 30 of July and untill now the 6 of August I haven't experienced this before does anyone know what could be causing it??? It started out as pink spotting then it turned into brown discharge now it's back to pink spotting.