Bleeding after sex

I keep bleeding after sex and have no idea why!

They done swabs for stds which was all negative. I'm now getting a smear in 2 days time... I'm just worried! What else can this be?

Sometimes after sex (very rarely) the next day my vagina hurts (even though he hasn't been rough)

I just don't want to worry and just wonders what else it could be. They have looked at my cervix and said there was something white on my cervix but they went to look again today but they could see has I had too much discharge