Sounds like she is ready to go. I know "Sophie" didn't leave her Mom's side the day she delivered. (That was on Wed morn)
She also vomited a couple of times and then she would lie down for awhile then get up and walk around then stop for a few minutes and just stand there then go back to her whelping box and lie down. She just wasn't acting herself so we knew. Hope all goes well and can't wait to see pics!