Sick or teething?

I can't tell if my son is just teething or if he has a cold. He's got a runny nose, really congested, fever and a cough. His gums are swollen and hasn't been sleeping well at all.  I don't know if he has a cold or is teething. He's not as active as he usually is.  I kinda need to figure it out because if he's sick I won't bring him around my friends babies. But if it's just teething I'll still go out with them tomorrow. What do you guys think?