mouse continually squeaks or purrs

Question
I woke up to my mouse squeaking this morning.  She has never done this before to my knowledge and I am home most of the day.  She is about 2 1/2 I think  (I was not her 1st owner).  I took her out of her cage and but her in a different enclosure while I cleaned her cage thinking it may help.  she was fine in the other enclosure but when I went to pick her up the squeaking started again and now in her newly cleaned home she is continuing to squeak or may a sound like (a knocking sound)she is sniffing.  She is running around on her wheel and sitting in her home lie normal but the sound is not usual. I can not think of any new surroundings or anything and I am not sure if this is normal behavior?  If it is not normal what can I do to fix it?

Answer
I would take her to see a vet right away as chances are, she has an upper respiratory infection. They should be able to give you some antibiotics to treat it. If she is as old as you say she may be having other issues as well, such as heart trouble. Better to be safe than sorry. :) Hope she does well. Make sure you keep her cage very clean until she sees a vet. Urine buildup can cause significant damage to the respiratory tract if amonia is allowed to build up. If she is housed on pine or cedar switch her bedding asap to something safe, such as Aspen shavings, or Yesterday's news. Carefresh can be very dusty, so if you are using this bedding try switching to something else. :) Let me know if you have any further questions. Good luck!