Clicking noise in gerbil

Question
I have 2 female (I believe Mongolian gerbils?) I got them in a pet store for my daughter last year. We have had no problems with them. We clean out there bedding every week(occasionally every two weeks if the bedding seems clean as they like to fluff everything everywhere). Lately one of our Gerbils, Anna, has been acting weird. We cleaned out the bedding, water and food dishes and put everything back in. Tonight I noticed Anna is breathing really hard lying on her side and she's "clicking". I hope she will be ok. Tomorrow, I am praying she lasts that long, I am going to call the vets and take her there on my lunch.

My questions are #1 what are warning signs they are getting sick?
#2 If she does pass on what happens to her partner in crime? Will she be lonely?

Answer
labored breathing and clicking noises are signs of respiratory infection. A gerbil not acting and acting different than normal are clear signs that something is wrong. If she passes away, her partner will realize she is gone and probable get depressed. Sometimes buying a new gerbil helps but the the new younger gerbil may fight with the older one. You could also try keeping the lonely gerbil occupied with treats and toys.