My girl is sick :(

My puppy has been sick the past couple days!! She’s so congested!! Her sister had the same thing and recovered in 7ish days. She has all of her shots and everything like that. Whenever she lays down she has post nasal drip the freaks her out :(

This is even worse for me than normal because my last dog passed away from tracheal collapse that couldn’t be remedied anymore. And it sounds very similar to this so I panic. She won’t leave my side because I somehow make it better for her? I’m not too sure. I have a humidifier going. I also broke down and gave her 1/3 of low dose Benadryl to help with the congestion and hopefully make her sleepy for a while.

I know there isn’t too much I can do but is there anything to help relieve it? She just went to the vet and was given a check up/clean bill of health. Totally clear lungs and no issues. Is there a decongestant for dogs? She’s just so tiny (5lbs) and I’d assume the phlegm is super bothersome since there isn’t much place for it to go! Thanks so much for reading. I just feel guilty that I can’t do anything for her :(