I am so glad I read your post! My 3-month-old was congested...for days, then weeks. I took him to an ENT but there is nothing really wrong with him. First, saline drops 2 or 3 times a day. Get the kind that spray. This actually helps shrink secretions; it's not just a worthless thing to do (like I used to think).
Second, buy a NoseFrida. It is made in Sweden and about $16. I had mine overnighted on Amazon. It is AMAZING. Those bulbs never work, and I worried about hurting his nose. With the Nosefrida, you just place the end of the tube on the nostril (so no risk of hurting inner nose), and suck in other end. Sounds gross, but mom does not get anything in her mouth. It's hard to explain, but it's a miracle. It got gobs out of my son's nose. Always use saline first, THEN use the Nosefrida.
Our little guy just got over a second cold (this time it had a cough with it too), but he's better now. This is our third child and I wish I'd bought this thing earlier. I figured the 126 good reviews on Amazon could not be wrong.
Also, we have a crib wedge by Dex that elevates the head. Baby uses this each night. (I have him sleep in his swing when he's so bad he sounds like a train, so his head is really, really elevated).
Babies and colds is just a bad combination. Hope baby is better soon! I cannot tolerate congested noses in myself at all, so I go all out for baby, but there is not much you can do for a baby compared to an adult.