Suddenly developed insomnia after drinking certain amount?

I’m 31 F and I’ve noticed the last few times I go out drinking I have insomnia. It doesn’t seem to matter what I drink, if I drink more than 2, I just can’t sleep. I feel tired though, but my heart is thudding and my mind won’t let me sleep. I’ve downed so much water my urine is clear.

I had 2 glasses of wine with dinner, and thought fuck it and had a whisky afterwards, and now I’ve been lying awake for 3 hours. My last drink was 4 hours before bedtime.

I’ve had a single beer an hour before bed and been able to sleep.

Before I got this insomnia, I used to drink maybe a whole bottle of wine over a weekend and maybe a whisky or beer. My sleeps weren’t great but at least I was unconscious. I’m not overweight and caffeine free. All the drinks I’ve consumed that resulted in insomnia are caffeine free.

I’m on holiday right now and I want to go out and party, but this is sort of ruining it, as I don’t have the time to lie in bed awake for hours, as it eats into my sightseeing time if I sleep in.

This has been happening for a few months now. What on earth is going on??