Last night, i had two 500 mg aceteminophen tylenols (acetaminophen). a few hours later i had two 325 mg nyquils, and feel awful ever since. too much aceteminophen?

Possibly: Acetominophenis also sold as tylenolr. Depends on version of nyquil you took. Generally in healthy patients we advise no more than 1000 mg every eight hours. Above that level and in patients with liver disorder, that dose could be even less. I would recommend contacting your doctor to see if you should have liver function tests. Acetominophen overdose can lead to liver failure.