Had unprotected sex yst.didnt penetrate all the way in&didnt ejaculate in.was only in for less than a min.had period today.will i get pregnant?

Unprotected sex: NO. Always best to protect. If no ejaculation then no pregnancy. Also if you have your period now, then you did not ovulate and not possible to get pregnant.

Q\always possible: Unprotected sexual intercourse can always lead to pregnancy. Although you say there eas no ejaculation, sperm cells can be present in pre-ejaculatory seminal fluid. I suggest always using portection and birth control. Monitor your menstrual cycles and seek contraceptive advice.

Pregnancy: Highly unlikely given menses. In mid cycle though could happen, though non penetration and no ejaculation argue against sperm entry. (Only takes one)

Not likely: Unprotected sexual intercourse without barrier contraceptive method, such as condom, spermicide, oral contraceptive increase his risk of pregnancy. Although there are controversies regarding the presence of sperms in pre-ejaculatory fluid, nevertheless, pre-ejaculatory fluid his discharge from the male penis during arousal, foreplay and sex. However, normal menstruation indicated no pregnancy.

Probably not: If your normal period started today it is unlikely that you will get pregnant this time but pother wise this is risky behavior if you don't want to be pregnant. The highest concentration of sperm is in the very first of the ejaculate and sperm on the vulva can swim and fertilize an egg. You need to begin a reliable method of contraception unless you want to be pregnant.

Slightly less likely: Less likely since you are probably not in your ovulation phase (period today, if this is a normal period). However there is usually a small amt of semen released prior to ejaculation. Sperm can survive for approx 5 days. Still check future pregnancy test for any missed period. Condoms always for future. Plan B is always an option. The conditions you describe seem to reflect a low likelihood.