Still congested, I hope that swig of cough syrup doesn't make me oversleep!
Lemons contain Synephrine , (OTC is Neo-Synepherine) which acts as a decongestant. Hot lemonade works very well. If you think you won't like the taste of hot lemonade, hot water will do fine. Either way you won't get any sleepy after-effects.
Oh, and PA swears that dairy causes him to have increased mucus, so maybe lay off that too?