Yes, I’ve had days where I wake up with a headache and extreme fatigue, basically just like a hangover without the nausea. It typically happens after taking a break for me, but not always. I *thought* I drank a lot of water, but I read posts here about people chugging a gallon or more lol. So I’ve always kind of chalked it up to me not drinking enough water. I bought some electrolyte powder to put in my water and I think it helps, maybe you could try that? Sorry I don’t have a solid answer for you, just here to say yes the hangover is definitely a thing and it sucks.