I had unprotected sex with my bf day after my period for about a minute could i be pregnant he didnt ejaculate?

Pregnancy unlikely: If worried, can do a pregnancy test. A urine test gives a reliable result 3 weeks after sex (3 weeks after when conception might have occurred), or 1 week after missing a period. If done sooner, a positive result is likely real, but a negative result may be due to testing too soon, and thus lead to a repeat test. If a woman gets her normal regular period, then she is not pregnant.

Yes but unlikely: Pregnancy has been documented from exposure on any day of a woman's cycle including during menses. These are rare in women who have regular cycles & are less likely if exposure was minimal. However, any erect penis can secrete sperm containing fluids & it only takes one to get you pregnant. Either use condoms or BC or this or future such exposures could end in pregnancy.