13 weeks old, not sure what it is?

My little boy is almost 14 weeks old. Just yesterday he started not feeling well I guess. He's usually very happy and very content so when he gets upset I definitely know something is wrong. He's been running small temps, he has a runny nose that's clear drainage, he's been drooling a lot, and he spits up more than usual. He still has wet diapers, and doesn't appear dehydrated. He just seems miserable. =( Is it possibly a cold? Could it be teething? I've read that teething follows the parent's pattern but I had two bottoms by 4 months, and my husband didn't get his until 13 months. What can I do to help soothe my little one? I'm leary of tylenol because I want to be safe, but I'm just wondering what I can do. Any advice is appreciated. =)