I was up almost all night last night with my dog. She's 11 and when I got to my parent's house (she stays with them every day while I'm at work) to pick her up yesterday my father informed me that she wasn't walking on one of her hind legs. I picked her up, put her into the car and did my best to examine her. I didn't find any thorn or sticker in her pads and nothing to indicate that she'd been bitten or stung by anything. She does spend a lot of time outside at my parent's house so she could have gotten into anything before I picked her up. She came in, laid down in her bed and pretty much remained in one place. This is unusual since when I watch TV she usually wants in my lap. She was lethargic so I took a baby aspirin, cut it in half and gave it to her. The swelling in her leg was so extensive it was double its normal size by about 7. At 9:30 last night she woke me up throwing up. This continued until almost midnight. There wasn't an unsoiled blanket anywhere in my house by this morning. I'm at work now, waiting to her from my parents as to whether or not she's stopped throwing up. They said if she shows no signs of improvement in the few hours since I dropped her off they'd take her to the vet. I'm not sure if she's been stung or bitten or what but on an 8 pound dog I'm not sure what kind of reaction she'd have if that happened.