Can you conceive the week before period?

I recall planning to get my period on or around 10/1. (I was bummed thinking I was supposed to get it on vacation) I still don’t have it. I’m not on birth control. I had my last period at the end of August.

While I was on vacation, my Husband came in me. We’re not really trying right now or atleast we weren’t 🤦🏼‍♀️ lol. Probably 9/30. I don’t know if my just tripping but I swear I felt a sharp mini cramp just the day before. (Could this be ovulation?)

I took a pregnancy test yesterday was negative. *now 6 days late

Long story short - is it possible to get pregnant the week your supposed to have a period. If so then how would that work with testing? Has it happened to any of you?