My female guinea pig Midnight has suddenly gained a ton of weight. I was holding her on Wednesday and she was fine, now on Sunday she has gained a ton of weight that wasn’t there on Wednesday. She is about 3 years old and is the only guinea pig in the household. We got her from a pet store 3 years ago where she was being kept with all females, we changed nothing in her diet and everything is normal besides her weight gain. Did she somehow get pregnant? Or did something else happen?