I got pregnant while my boyfriend was away???

Hi y'all. I just came back from my obgyn and found out I'm 9w2d pregnant. Which means I got pregnant at around August 6th.

However, from the 31st of July to the 14th of August I was away on a vacation. Without my boyfriend. There is absolutely no way I had sex with someone else.

So I'm wondering how specific these 9w2d are.

Please help me out. I'm very scared to tell my boyfriend.