I looked up Dostinex and there weren't any contra-indications that had to do with food, just other pharmeceuticals. Side effects do include constipation, dizzyness, vertigo, headaches, the usual etc. So you shouldn't have a problem. It said you weren't supposed to miss a dose.
People have really varying degrees of weight loss. To ensure a permanent weight-loss, do at least one Liver Flush after your fast. I lost a pants size after doing 2 flushes recently, without even dieting much! :) Start reading up on how to do it here on CureZone and read this site for info on how the liver manages fat and weight, not the thyroid so much like people think: