Tips to avoid throwing up + getting a headache?

The caption kinda speaks for itself lol but to give some more context; I used to drink a lot when I was 14-16, I could really tolerate drinking but now (I’m 20, legal drinking age here is 17), I can barely drink without either getting extremely sleepy, get a tummy ache or a headache.

I just resorted to not drinking at all but tomorrow I have a friend’s birthday and it will be an open bar and I kind of want to get a bit drunk and have the type of fun I used to have when I was younger lol. I know it’s not guaranteed that I won’t have 100% none of these symptoms cuz they just come with drinking alcohol but do you guys have any tips in general? Preferably nothing that involves drinking straight alcohol with no mixer cuz that’ll just make me gag