my guinea pig was like that when she was pregnant.
i think carrying her is stressful for her. you should carry her less especially when she's close to giving birth.
to know if she is pregnant, check if she's eating and drinking more, if her body has grown, you would also feel her babies when you touch the sides of her stomach (this would be felt at about 7 weeks during her pregnancy)
some of the signs that a guinea pig maybe close to giving birth are: eating less and nesting
hope this helps....
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