Could she really be pregnant or messing with me? We had one time thing and I used protection

Ok. I had sex with this girl like I think 4 or 5 weeks ago, December 13th to be exact. It was a one time fling thing. I used protection, I even switched out the condoms 3 times due to lack of lube during the act. I don't think I ejaculated. I mean I would know if I did right haha but I really don't think I did. In fear of condom breakage I still checked the condoms and filled them up with liquid just to check if any of the 3 has broken. But it was no leakage... Today January 12, she tells me ahe went to the Dr today and the Doctor says she's pregnant, that's what she tells me. Now I want to believe her because she's my friend and I don't think she'll play with me like that but then I also think well I don't remember ejaculating and we did use protection soooo yea.... I'm stressing right now because it's like man she's super serious.