Scareddddd

So I had my period from the 29th of June - 5th of July, and a few days ago I had sex with my boyfriend and noticed there was bright red blood on the sheets, not much but still alarming! And since the day after, I've experienced brownish discharge when I pee but not in my underwear, what is happening!? Someone please help 
Also - we did do doggy style for the first time in agessss so could that have caused the bleeding? 
Really need some answers people! Xxxx