Anyone help but best if your a doctor whats the chance of me being pregnant again ?

ok i just had a baby boy 4 weeks ago. well my postpertem bleeding stop bout two weeks after delivery . me and my boyfriend was messing around by him touchin his to my virgina we didn't have no cloths on from the waist down and we didn't have tho but i think he may of came or pre came near my virgina. two day later i started spotting only lasted for bout a day whats my chances of being pregnant again:(