A.,
Try any or all of these ideas:
Use a Neti-pot or NeilMed Sinus Rinse bottle. They sell packets of saline mixture to be mixed with cooled boiled water. You rinse your sinus passages with the mixture and that rinses out the mucous. Less mucous gets down into your throat, which means less coughing. -- During allergy season I rinse in morning and at bedtime. Sometimes I have to use two bottles of rinsing to get rid of mucous.
Use the little saline spray bottles in between the above rinse treatments, to keep the mucous liquid enough to move it.
Take guaifenison (sp?). I'm not sure how this OTC drug affects nursing/babies - read up on it! Anyway, guai thins and loosens the mucous so it will cough up easier.
Take odorless garlic capsules - antibiotic and antifungal. If you have a cold or virus, it will help you get over it or at least not get worse.
Take Vit C - strengthens the immune system and shortens the length and severity of a cold.
Use a humidifier, especially at night - keeps the sinus passages from drying out. Dried up mucous blocks the breathing passages and is harder to cough up. -- During the day, you can move the humidifier from room to room with you and baby. This can help a lot.
Do a hot steam treatment several times a day - several ways to do this: boil water on stovetop and breathe in steam or wet a washcloth or handtowel, squeeze it out, then heat to steaming in the microwave. Use common sense here - wait for it to cool just a bit. Handle it with a dry towel so you won't get burned. Breathe in through the damp washcloth, so the steam will loosen the mucous in the sinus passages and you'll be able to expel it by blowing your nose or clearing throat or coughing.
Your goal needs to be to keep the mucous liquid enough to be able to expel it by blowing or coughing. Be careful when you blow your nose - don't blow too hard when you're completely blocked up because you can injure your eardrums. Pay attention to your body.
Bless you!
A.