Sudden Illness With Young Rat

Question
I have a "fancy" rat that I rescued from a tank of feeders in the back of an Uncle Bill's pet store. When a rep I asked got clearance from a manager, he led me to the back where the tanks were. The conditions weren't particularly bad, but not exactly fresh. When the tank was pulled out and the lid lifted, as expected, all of the rats fled to the far side of the tank except for one. I reached in and was able to pull her out of the tank without any problem at all. After that, I immediately knew I had to get her. She was energetic, curious, and very sweet. So after purchasing her at "feeder" price and signing a health guarantee, I had my new rat. Placed in aspen bedding and given some timothy hay to chew on, she stayed energetic and very curious for about a week. One day, I noticed worms coming out of her anus immediately after she had defecated. From my research, it's very clear that I should take her to a vet. It was a clump of very tiny and thin worms that were yellowish in color. It seems as if they died, because shortly after I discovered them, they stopped moving. I was concerned, but since she was acting healthy, I set the notion aside. Here it is a few days later, and I've been noticing a progression in lethargic behavior. I used to own quite a few rats from a curiosity to breeding, and when I saw her, I immediately knew something was up. Her fur was fluffed out, her posture was different, and her eyes were sleepy looking. Despite her appearances, she would kind of snap out of it and go back to normal with being active and playing with me. Now for the past two days, she appears to have labored breathing in short, quick gasps and feels/looks like she's lost some weight. I don't think her bedding could have caused this problem, and, looking to be no more than two months old, I'm curious to the worms I saw playing a role in her sickness. It's saturday evening, so no vet office is open, except for an emergency clinic, and being laid off, the little money I have left I have to keep a tight hold of. Are there any at home remedies for respiration issues that I would be able to use? When I had given my grandparents a couple of my rats a few years ago, I read that echinacea oil was good with clearing some of it up. Do you believe that would help? Any other general advice you could offer?

Answer
Two ways of doing this:

Go to your vet, have them do a fecal, wait two days or so for the results, then buy a parasitical treatment from them (most likely ivermectrin) and some antibiotics from them.

Or: Go to your local tack/feed store and buy some ivermectrin paste, sold for horses. Give your rattie a bit of ivermectrin - about the size of a grain of rice, no more - once every two weeks until she no longer seems to be passing worms.

Most likely, these are either roundworms or tapeworms. Either way, ivermec will take care of it. Just keep on it, encourage her to continue eating and drinking, and good luck!