Hi, On The 14th October This Year I Had Unprotected

Hi, on the 14th October this year I had unprotected sex with a friend, he didn't cum inside me it was only pre cum. I asked him if he was clean and he said yes but I didn't believe him, it didn't last very long either but now I am pregnant with his baby which makes me think he did cum inside me. If he was infected with HIV what is the possibility I could of caught it.
Thank you