8week old rat not growing, labored breathing, collapsed and swollen penis?

Question
Hi, i am hoping you can help me. Two weeks ago i bought two 6week old male fancy rats, from the begining they were both a little snuffly and the rat in question has always seemed like his breathing was a bit labored. I took them both to the vet who prescribed Baytril which they have just finished with not alot of improvement. Also during the two weeks one of the rats has almost doubled in size while the other doesnt seem to have grown at all. The small rat today while out of his cage began to gasp for air and when i opened the cage door crawled onto my hand and then collapsed, i was convinced he was dying but after a couple of minutes he stopped gasping and sat back up. Now his breathing is still labored and he is quiet but otherwise normal.
The other thing concerning me is that he appears to have a very swolen or enlarged penis? I have an appointment at the vets tomorrow but i am wondering if there is anything i should do in the meantime?
Any help would be greatly appreciated
Thankyou

Answer
Hi Leanne

This is not a good thing at all. Please let me know your location so I can find an ER vet for you that sees exotics. His penis may be swollen from a condition when the foreskin is stuck over the glans and this can cause him to not be able to urinate and can cause the penis to swell. This is a serious emergency.  Also, the gasping is not good either. If he has pneumonia he would gasp and wheeze and this could kill him. He needs aggressive antibiotics and put in an oxygenated isolette and nebulized with baytril.  Baytril should be used for 30 days, but if it isnt working alone, doxycycline is added. If both fail after three days, another medication should be used.
Please let me know your area and I will find a vet for you that may be open tonight.