A little late for a reply if you wanted to go to sleep when you posted, but you could be sensitive to the Dyphenhydramine in antihistamines (it's also in motion sickness stuff and sleep aids). I get a HORRIBLE feeling if I take that stuff and haven't taken cold medications for the past 30 years. The best way to describe it for me is that I feel like my head will explode, my heart pounds, when I am ready to fall asleep I panic awake real fast because it feels like I am "sinking into my death" - and yes, things feel WEIRD too.
The feeling it gives me is so scary so that's why I don't take anything like that. Nyquil was the worst!!!! But even a tablespoon of something like Vicks does it, but not as intense - but like I said, I haven't taken anything like that in 30 years.