Definitely call either your OB or your son's Pedi. Whenever I have a cold, I drink lots of OJ and get lots of rest. When my daugher was younger, I would just take her into the bed with me so I could nurse on demand and still get some rest.
You could also try taking (and I'd confirm this with the doctors, since each one seems to have a slightly different opinion) Sudafed or Tylenol Cold. Those were both approved for me. Yes, it does have the risk of drying up your milk supply, but my doctors had told me to increase the fluids I was taking in (which you should be doing anyway for a cold) and that would keep my supply up. I took the minimum amount of medication I could get away with and not be miserable (i.e. I'd try with 1/2 dose and not take it again until I felt I really needed some more medication). My daughter's Pedi also brought up the point that being miserable and staying sick can also decrease your supply, so it's better to take in some medication, counter it with the water / juice, than to be miserable.
Feel better soon!