Heart racing after 1 drink

Hi, I (f,23) am a student who still likes to party. I used to drink a lot in lockdown like every Friday and every Saturday. But in the past year I have started to drink less (I sometimes take months off of drinking at a time) but now I drink 1 pint and my heart races until the next morning. I don’t know what to do because I feel like I can’t enjoy drinking anymore, will this be my life now?

I am very healthy I go to the gym 4-5 times a week. I am on a diet right now could that be the problem?