I'm in a pickle

So I had sex with a coworker on the 23 of November, well I wouldn't call it sex.. more like he did penetrate but for the most 30 seconds.. no ejaculation.. had sex with my partner he did ejaculate November 26 my conception date says anywhere between November 26 to December 4th.. I'm pregnant now and I'm in the skyla iud.. can this baby still be my partners kid?? The coworker was a mistake that's why I stopped it.. idk I need like a medical view I think.. or what the probability is?? I know I sound like a bad person  the website I'm using says I'm about 6 weeks