There is always the chance that your 18's were growing with you. So even though you lost 10 pounds, it more or less brought you down to the "true" 18. Or what I like to call "off the rack" as oppossed to the worn one in your drawls. I usually like to allow 15 pounds a size and not the ten rule. Also you may have to allow the inches to catch up with the weight loss. I know, this is not what you want to hear. But soon you will be throwing those 18's into the discard pile!