You CANNOT get pregnant from anal sex.
How old are you?
Have you ever been talked to about sex? From your parents? A sexual education class at school?
Use condoms. STDS can spread through anal sex and oral sex as well.
Sex Ed 101:
A penis has to actually enter a vagina to make a baby.
Sperm has to meet an egg for pregnancy to occur. Eggs are not found in the rectum, they are found in ovaries. The ovaries connect to the uterus via fallopian tubes. If there is no sperm in the vagina, they can't actually reach an egg.
Be careful. Protect yourself. EDUCATE yourself about sex before having it.