Should i call the dr for congestion?

My baby is 4 weeks old and a little congested. He doesn’t have a fever or anything just a little clear mucus and maybe eating a little less but still peeing and everything. We did finally go outside the other day bc it was the nicest and warmest day since he’s been born so i don’t know if that has caused he congestion or what. Should i call the dr or an i jumping the gun? Tia.