how much weight loss is too much weight loss?

 I started almost where you are and lost at the same rate as you.  I got down to 137 lbs at 14 months out then over the next 18 months I gained about 30 lbs.  I am five years out as of Jan. and have maintained my weight after the bounce back.  My body feels comfortable here.  

Dr said I lost lean muscle mass so when my body adjusted to the loss, I started gaining muscle.  I am super flabby in my arms and thighs.  I did not exercise much either.

Good Luck with your journey - you will probably loose more in the next year.  

Rhonda