whats happening with my mouse?

Question
pet mouse, almost 3 years old so i know he's probably near his lifespan, but until earlier today he was perfectly normal, active, eating, drinking.  Tonight he's suddenly not wanting to move, eat or drink, and he is breathing rapidly, it sounds like a clicking sound.  What could it be?  Dying of old age, an infection of some sort?  Is it worth pursuing with a vet?  Thanks.

Answer
Hi Laura,

I'm sorry I didn't get back to you sooner, and I hope he is doing okay.  Like you said, he sounds fairly old, and I am not sure how much you can do for him.  The clicking may indicate a respiratory infection, but given how swiftly it came on, I am not sure how effective treatment would be.  If he is still with you, you can try getting him to a vet quickly for a dose of antibiotic, and then get him on something in his water - but that really is the problem.  If he will not eat or drink, he can't get the medication or nutrients he needs to heal.  Given his age and, again, how very suddenly this happened, I think it may be his time, if he hasn't already passed on.

My thoughts are with you and him, please let me know if there is anything else I can do.

-Tam