Help--sick 13 mo. old

OK, so I'm starting to get a little concerned about my ds, and I'm not sure whether to take him to the doctor or not. He ran a high fever (103.5) and was throwing up about a week and a half ago. This lasted about 24 hrs. He seemed fine for about 4 days and then started with a fever again. It lasted for a couple of days (fluxuated from 99-103) along with a cough. Then the fever went away on Tuesday evening. He still has the cough. He had a bit of a rash on his face that lasted a few hrs. I thought it might have been Roseola and I figured it was just going away. But yesterday and today he has been increasingly fussy. He is wanting to nurse non-stop, and is barely eating any solids. He gets upset at EVERYTHING. He will get off my lap and start crying. He will drop something and cry, etc. This is my normally cheerful, happy-go-lucky little guy. He will run around happily for 5-10 minutes and then suddenly get really upset and start screaming and act really angry. Oh, and he has a swollen lymph node. We have checked his ears and throat and they look fine. I did give him some soymilk yesterday and this morning, when I needed a break from the nursing. Could that be affecting him like this (he hasn't had any before)? Also, he doesn't have any teeth yet, so does this sound like he might be teething (his gums aren't red or anything). I guess I'm just starting to be concerned.

Any advice would be appreciated. TIA!