Question about precum, pregnancy and ejaculation?

Hi, I'm really concerned about precum and ejaculation and pregnancy. Today I was having sex, using a condom. After he ejaculated, I took the condom off and gave him oral, then he put it inside of me, and took it out immediately. Is there a possible chance of precum with sperm getting me pregnant, and can precum even occur with sperm in it after you ejaculate? He ejaculated like 2 or 3 times before. There was no sperm on his penis before he put it in. I'm pretty positive he didn't have any precum in me if he could, it was a few seconds and there was nothing on the head of his penis after. I'm just a bit concerned, thank you for anyone who answers.