7 week old baby has a cold? help?

First time mom here, and I think my 7 week old has a cold, he keeps getting snotty stuffed nose, sounds congested, but took his temp rectally and it was 99.0 so no fever. Do I need to take him into the doctor? hes eating just fine, but seems a little bit more fussier and sleepier then usual. Is there anything I can do to help him feel better or anything? Thanks =)