Diabetic Dog?

I think my dog may be diabetic. I got her from a puppy mill and she was very thin. I thought she was underfed. My vet has recommended me to get blood work done which I am doing tomorrow. Her symptoms match many of the ones I have been reading on different sites. She is a 30 pound ten month old boxer. We have to take the water bowl away from her because she will drink as much as we give her and then throws up. She urinates quite often. She is housebroken but seems that she can not always hold it. Her nose is always dry like she is dehydrated but she has plenty of water each day. Are these common signs in anything other than diabetes? If so, what else might it be? And also, what is average cost to get a dog stabilized on insulin and costs for medication per month? Thanks for any help!!