I use DayQuil/NyQuil when I get a cold and in my case, it's always worked well. It suppresses the symptoms and lets me carry on with my day-to-day. I did try once going 1 week without it and it was hell.
It takes it down to just the Tylenol, the DXM (, plus the antihistamine in the NyQuil), and the great slightly tearable taste for the ritual of "time to pretend I'm not sick for a little while".