Yes, I can totally relate on the near obsession. It's tough, but we have to trust ourselves that we know enough to just maintain. We also have to be realistic about what happens to our bodies as we age. I'm not 13 anymore, and I have to remind myself of that every single day.

I'm no expert, but I'd tend to think that fretting over half a pound is bordering on obsessive. If your family is noticing it, it sounds like it could be becoming a problem. Try to let go. There are healthier, more productive ways to express control in your life.

Take care...

(edit: ) Oh, and one more small point: if you were at that low weight on a low fat diet, you probably had insufficient muscle mass. Now that you eat properly, your body actually has the muscle that it's supposed to have, so it's not fair to compare "then" to "now".