slow piggie

Question
I have had two sisters living in a large cage together for almost a year now. One is usually very timid (Polly Prissy Pants) and the other is typically very active (Babs). Babs usually stands up the side of the cage to see us or to get a snack, but over the last couple of days, she has become quite inactive and slow. I gave her a snack, her sister came over and took it right out of her mouth (which is pretty typical) and Babs just sat there staring. Usually, she'd go after her sister and take the food back. I give them one vitamin C tablet a day and, although she refuses it a percentage of the time by taking it but dropping it on the bedding, she is usually pretty curious about it. She didn't even approach me when I gave her sister the tablet. I know it's only been a couple of days, but this behavior is nothing like Babs.  I was thinking about this today...I recently began giving them dandelion greens from the grocery store. As soon as I get them home, I wash them off and keep them in a ventilated bag. I give them about 3-4 greens each. I was thinking that since this is kind of new to her, could it be too much? Or did I not wash them enough? We were giving them parsley before but thought they'd enjoy dandelion greens much more. She does seem a bit thin. She has always been very fit and lean, but her sides seem a slight bit sunken in, nobody would notice except for me and my boyfriend who see her each day. She seemed to be more responsive lastnight when I picked her up to weigh her. It's hard to say what she weighed before I noticed the behavior change, but she's 905g now. I don't have much of a reference for her weight, but before she got pregnant in February she weighed 935g. We checked her teeth lastnight and they seem fine, so she shouldn't have any problem eating. She continues to groom herself like normal. When picked up, she usually grabs onto my hand, but I can't tell if she's not doing it or if she is just too weak to try. I did see her run quickly when her sister jumped. Is there something I can do at home without taking her to the vet?

Answer
Hey, First try not giving her the dandeloins, what you are doing is fine by washing them and such, but they could be upsettting her. Is she eating normally other than that? Does she go to the bathroom well? I am not sure what else it could be, you might need to take her to the vet just in case for saftey, give me some more clues on her behaviours and maybe I CAN help some more. sorry!