It does seem strange that he would be vomitting and coming up lame in only one foot at the same time. Hopefully it's just a very strange coincidence. Keep an eye on your dog overnight until you can get to the vet. It's a fairly good sign that he's sleeping soundly...and not restless or showing irregular breathing/panting, I assume? I can't think of what else you could do at this point other than watch, keep him comfortable, and perhaps withold food (but not water) until the vet has a chance to examine him. Has he pooped since he vomitted?
Solomon - black DSH - king of kitchen raids (11)
Gracie - Mutterooski X - scary smart (9)
Jaida - GSD - tripod trainwreck and gentle soul (4)
Heidi - mugsly Boston Terrier X - she is in BIG trouble!!! (3)
Audrey - torbie - sweet as pie (11 months)
Patrick - blue - a little turd (but we like him anyways) (6 months)
Boo, our Matriarch (August 1 1992 - March 29 2011)