Hi. I Wanted To Ask A Question! One Month Ago

Hi. I wanted to ask a question! One month ago i was with my boyfriend, and i was on his legs and he ejaculated. He was wearing underwear and jeans an i was wearing a small thin pad, underwear and shorts. His jeans was a little bit damp. Also i was waiting my period that day and it came 3 days later. Is there a chance of getting pregnant? Thank you!