Why does alcohol give me a horrible headache even though I drink it every night?

I’m wondering why this happens to me cause 5 years ago or more I’d do the same and never even wake up hungover or anything,I should add that I have severe fibromyalgia that’s gotten worse in the last two years. Unfortunately this is why i have a few drinks every night to ease the pain and help me sleep through it along with marijuana. At the time it helps but the next day I feel awful,happens more if I drink wine so I usually stick to Tito’s. Could it be the fibro or just cause I’m getting older? I’m Only 31.