My girlfriend bled during sex, markedly little, a week after her period and shes be on the pill for 3years, why?

My girlfriend and i had sex in the order of a week after she had her interval, and she has be on the pill for three years. This has never happen before and she is worried that it might be something serious. I expect she's over reacting but she's really worried so if anybody can relief me please tell me. It be very little blood that be on the bottom of my shirt and a little bit on my bed sheets. She didnt bleed afterwards and didnt even awareness she bled during sex. But since i showed her the blood (big mistake) she's been freaking out. Please lend a hand, i dont want her to worry, and im sure its nil serious. Thank you :)
Answers:

Shave my private area?

Its merely due to a bit of tenderness contained by the uterus after periods, which is relatively natural. girls should watchfulness for their better health and own a healthy drinking habbit to overcome this type of small problems.

What happen when your Bartholin's Gland become blocked?

Have her go to the gyno for a check-up and pap smear. This will put her mind at allay. It could have be that there be a little clot contained by the vagina that became dislodged or perchance you were a bit rough?

Please helpis this normal?

It sounds resembling there wasn't satisfactory foreplay and you were possibly a moment or two rough. Next time spend more time warming her up or use some lube.