There are a number of problems that can have these symptoms, you should take her to the vet to be examined, in order to evaluate her condition and determine course of action.
Your dog seems to be in a lot of discomfort. At her age it could be anything from organ failure to frail bones. I would make an appointment with your vet and get a physical examination for her to find out exactly what the problem is. Waiting longer could make the problem worse.
I hate to give this news, but it sounds like some form of organ failure. I assume that she isn't lying down because it hurts her to. You need to take her to the vet to see if there is anything that can be done.
It sounds like the dog is in alot of pain you probably should take her to the vet and see what they say about her behavior. If she is pregnant she may be in labor and need the puppis taken C-Section.