Bad NyQuil reaction

I took NyQuil last night, slept like a baby. However I didn't take it until 5am when I was desperate for sleep. I woke up at 9 am dizzy, nauseas and shaking. My face was all pale and man I felt drunk. 
I handled it like I would if I had drank alcohol because it felt like that's what I did, I drank water and ate some bread and now all the sudden I'm better. I might go back to sleep soon now that I don't feel like I'm going to vomit. Could it be because I didn't eat before I took it?