I'm wondering because I vaped it yesterday for the first time in quantity, I've used up almost my whole bottle before, but always in small amounts mixed with other flavors. I felt amazing afterwards, assumed it was just a good day, but today I left it at home and vaped key lime pie and mint all day. I ended up feeling like crap by the end of the day, headaches, lack of focus, all the rest I thought I was over. I vaped until I made myself ill on the way home, and still felt like crap. I figured maybe I'd overvaped, but the headache got worse with time, I vaped another ml of tobacco flavor, and it was gone. I'm a little annoyed, because until now I was doing ok with any flavor, I don't want to be stuck with one I need to have regularly.
I'm feeling great now, which makes me suspect it must have had something I was missing, and now my body is being way more demanding to get it.