Is it safe to mix alcohol and Nyquil?

So, I wasn't feeling so great this morning as I had some cold or flu and my friends dropped by and started making screw drivers. I had one and yesterday I drank a little bit, as well. I'm starting to get a cold which means I'm not going to sleep that well tonight, but I really need to because I have a three-hour drive tomorrow. I kind of want to take some Nyquil so I can sleep, but the back of the bottle has a little warning about taking Nyquil if you drink more than 3 alcoholic beverages a day. I definitely don't drink THAT much, but since I've had alcohol less than an hour ago, I'm wondering if it's a good idea to take Nyquil or any other sleep aid.