Could i be pregnant? Throwing up while “drunk”

Tonight me and my friend decided to drink a bottle of honey jack daniels. I drank 2 shots in a mixer and decided to take a shot straight up with a chaser. Literally 2 seconds after i took the shot i felt sick and ran to her bathroom and threw up everywhere. I wasn’t even drunk let alone buzzed. My period is also 3 days late now. I started birth control a week and a half ago but wasn’t on it before and had unprotected sex about 5 times between my last period and since i started BC. Could i have thrown up because im pregnant? Or because i just dont like the taste of alcohol? Its odd for me to just throw up right after taking only 1 shot like that. What do you ladies think? After this i didnt drink anymore. I also took a pregnancy test 2 weeks ago just because and it came up negative, but it was also a little too early to test..