my calie

Question
I've had Calie and Cobalt about 1.5 mths, both are girls.  Cobalt was outgoing from the start and Calie a little more shy.  In about the last week Calie has gotten very fat and two days ago played less and last night didn't want to do anything but cuddle.  I'm really worried.  I thought maybe she was constipated but it isn't just her tummy that's fat, it's through her whole body, cheeks included.  She doesn't seem to be in pain, can move and jump around still, she will take treats but I don't know if she's eating their normal blocks.  I'm going to feed her some baby prune food tonight and see if that helps.  I haven't seem her poop, which is what made me think constipation, but I am not seeing a decrease in the amount of poop in the cage.  Money is extremely tight right now, so I can't afford the $70 exam fee (it's not even treatement just to see her). Some unexpected things came up in the last month, otherwise I wouldn't have got the rats knowing I wouldn't be able to afford the vet if they got sick.  Any advise on things to try?  I know she was up playing some in the night I checked on her, but yesterday she didn't leave the little house or my shoulder.

Answer
Sudden weight gain can mean retention of fluids, which can either be heart or kidney related.  The full face would not be caused by constipation, but edema instead.

Unfortunately if this is the case, she does need a vet. I understand how tight things are now days when our economy is such a mess, but unfortunately this may be something only a vet can help with.  My hands are tied in situations like this.