could be it wasn't all the way gone and plus ruff sex will do it . but i don't think it nth se::: it happen 2 me be4 to my doc say wasn't nth 2 worry bout
I would monitor your periods, it may not be anything, or it may be something to go speak to your doctor about. Stress also can play a huge role on periods and they can act weird in many ways. My girlfriend told me she had lost her job over 7 months ago & since then didn't have a period and wasn't pregnant, she started working 2 weeks ago & she now has it again. It was all stress related. If you monitor your period & you see that this is happening more often & possibly w/pain? I would go see the doctor just to make sure everything is ok. There are many things that can be causing this and we are not doctors. I suffered from Endometriosis and I had dark brown periods w/pain, ect. but it just didn't happen one day, it was months of these symptoms that lead to me going to the GYN when I was first diagnosed. Good luck.
bleeding during sex is common as u might know....may be it can be cervicitis ...go to gynaecologist once ....that will really help u as she examine ur cervix vagina ,may advice u to get ultrasound if he suspects fibroid....but make sure to visit doctor only after bleeding stops