I'm so sorry to hear you and your baby aren't feeling well!
To help with breathing, turn the shower on hot to build some steam in the bathroom and stand in there with your son to breathe in the moisture.
A less expensive vaporizer ($12.00 at Target, Walmart) is by Vick's. Of course, it's warm steam, as opposed to cool air from the humidifier, so you want to make sure it's placed up high where your baby can't reach it. I think the warm steam feels more comforting, but some believe it keeps germs around longer since the air is warmed. You may need to add a SMALL amount of salt to the water to get the steam going.
Another thing that works really well is to rub BABY vapor rub on your son's feet then put on his socks to sleep. Sounds crazy, but it helps to relieve coughing and to open air passages. This way, it's not on his chest where he can touch it, then get it into his eyes or mouth. It works well on grown-ups, too!
Good luck to you!