if there really is a chance I could be pregnant?

Ok so I had sex with my t boyfriend on March 8 and my last period ended on February25. While he was trying to break my you know at first he didnt have on a condom but after he put on a condom. After this I wasn't really worried about pregnancy until I started reading up on some things and found out that you could possibly get pregnant from precum if you were ovulating so I took some ovulation calendar/calculation test and since my period is 24-25 day cycle they said I was most fertile during March 1-7 so I was hoping if someone could please tell me if I'm just worrying too much or if there really is a chance I could be pregnant