I think lots of VSG'ers (and others) see things slow down at the 6-7 month mark.  For one thing, we're smaller, so the calorie deficit isn't as large and probably our metabolism may be a little slower now that our bodies are used to the low calories we take in (c25k should help with that).  Also, to be totally honest, I think a lot of people start going off their plan around this time after having achieved  a lot of success (not saying this is the case with you at all, but I do think it happens). 

Perhaps you're possibly putting on a little muscle?

Others have given some good advice - make sure you're getting enough calories of the right kind and just keep going.  Stalls won't last forever.

Our bodies can do some whacky things.  I was essentially stuck at the same weight for about a month and then suddenly in a three day period dropped 6 pounds, which have stayed off.  Not really sure why I was stalled, and certainly not sure why the big loss suddenly occurred!