only went in once, and I do not know why I am bleeding...

You took a chance and you could be pregnant but it is really too soon to tell.

Blood might be from the tearing of your hymen (losing your virginity) or might be from your period, though is probably the former.

Give it a couple of days and it should have settled by then, but if it hasn't you should consider seeking a medical opinion...

Blood is most likely from the tearing of tissue (broken hymen) and the stretching of the vaginal walls. I will give you the good news and the bad news of your encounter.

Here is the bad news...I hate to alarm you, but ANY time a penis enters a vagina, the possibility of pregnancy exists. When the penis gets erect there are preejaculatory fluid that is released to kill any bacteria from urine in the urethra. Unfortunately, that fluid has semen in it and can make its way to the tip of the penis and if it entered your vagina far enough, it is possible that some semen made its way in.

Now for the good news...most likely, you are not pregnant because despite what a lot of people are led to believe, the vagina is a VERY hostile place for foreign bodies like bacteria, and that includes semen. Semen only has a small chance of surviving in the lower regions of the vagina and has a much better chance of surviving if it is ejaculated into the vagina during sex. The further the sperm has to travel, the more likely it will die before reaching the egg.

So, most likely, you are not pregnant. I would give it a week or so and if you could get a pregnancy test (and the $1.00 one from the discount stores are probably just as good as the others for a positive or negative answer. No need in spending a great deal of money on something like that.

My opinion would be to not have sex again until you are older and possibly married, but if you are adamant about having sex again, please use a condom. Lubrication (KY Jelly is the most popular) might eliminate the roughness. I wouldn't advise unprotected sex to anyone who isn't married and doesn't want kids. You are still young and you aren't ready for kids yet.