My guinea pig is dying? (part 2)?

I tried to put her in a shoe box and I tried to give her carrots and celery. She isn't eating it. I kept her in their for like 15 minutes. She is making a weezing noise . She also went to squeak but a little crack came out of her mouth. When I took her out of the shoe box, I noticed their was ALOT of pee but NO poop. I am really scared about her. I also weighed her and she is not close to 1 pound. Please help! I lost a guinea pig 3 months ago and I don't want to loose my new piggie!