B.C.
See a doctor and make sure it's not whooping cough.
That would be very dangerous around so young a baby (and too young to be vaccinated).
Over the counter medication might help ease the symptoms but it's not going to make you any less contagious.
Assuming it's not flu or anything else but a plain cold virus, some coughs just go on for a long time.
My personal record was 8 weeks (doctor verified it wasn't pneumonia, bronchitis, allergies or anything else) and my ribs were getting sore.
Try a heating pad on your chest and breathe in steam when ever you can.
Use a neti pot (rinse out your sinuses with salt water as often as you want).
Do not try to dry it up - that only makes it worse.
Stick with Mucinex to keep the mucus thin and easy to cough up.
Drink plenty of fluids (water, tea, chicken soup).
Keep the humidifier running in your room at night.
It will eventually quit sooner or later.