I am 4 weeks PP. Help.

My SO and I had sex when I was 3 weeks PP. Stupid, I Know. But we haven't done anything since. (By this point in time I had already stopped bleeding and it had just been discharge.) I called my doctors office and even let them know so it would be in my chart at my 6 week PP check up. 2 days ago I started spotting. Now today it is full blown bright red blood and it is getting a little heavier. Is this something I should be worrying about. Should I contact my doctor again? I am a FTM so I am not sure what I need to be worried about and what I need to be looking for as warning signs.