Well done, that's fantastic.
Everybody's different as far as weight loss is concerned. Like Helen said thats a stone and a half in a month!!! If you average out at 3lbs per week thats almost a stone a month which is pretty good. You wouldn't get that kind of loss at slimming world evefry week.
Be proud at what you have achieved.
Did you take any measurements at the beginning? You will also be losing inch's too.
Emma x