Help! My dog seems sick?

Since yesterday my dog has been acting really weird. She threw up in my basement and then just was acting awkward and has been spending a lot of time outside laying in the snow. I went out side to see if she had thrown up any more and I found several more "blobs" of throw up. She wasn't really interested in food yesterday also, I was trying to give her snacks but she wouldn't eat them. She hasn't eaten at all today and I have watched her outside and one time it looked like she was going to poop but then she didn't. This morning she lied outside for hours, which isn't normal for her at all. I'm wondering if maybe she has eaten a sock or underwear or something and just hasn't been able to cough it up or poop it out. She was laying down a lot and maybe I'm just paranoid but her stomach area seemed kind of swollen. I also noticed that she was twitching slightly. Nothing major though.

She is a yellow lab and is only 4 years old. She is the kind of dog that will eat anything. If we left a bag of dog food open and within reach of her, I'm pretty sure she would eat the whole thing.

Please help, I'm started to get nervous :(

Thanks in advance !