First and foremost, WELL DONE!!! 6 stone is an amazing achievement and you should feel very proud. Secondly, tell your well meaning friends and family that yes, you do feel and look a hell of a lot better, but people carry their weight in different ways and you still feel you have some more to lose, and that you have absolutely no intention of becoming dangerously thin or ill as a result so they can rest assured that you are in fact aware of what you are doing.
To them, they see a huge change in you, and are reacting to that, but you live with yourself all the time and the change is more gradual, and your mind will take longer to catch up to the reality of the changes you have made already. You probably have some idea of the weight you want to get to, and the size you want to be, and because you aren't there yet, you see yourself as still too big. Try and challenge yourself when you think that way, reassure yourself that actually, you are a lot lighter than you used to be, and you can now fit into pretty much every clothing range available, even though you still have some areas you want to target.
You'll get there. And you will know when you have.