Are you male or female? and how old?
A woman's weight can easily fluctuate during the day like that especially at different times of the period cycle. Water retention can cause me changes of up to 6 pounds either way in a matter of 3 days or so. I can swell and loose that fast without changing diet or excercise.
And if you are a woman, my next question would have been how have your periods been lately.
Otherwise, man or woman, I would ask your doctor to see if you can see an endocronologist if you already haven't. Could be hyperthyroidism. But your age and sex is a critical factor here because if you are a you person (under 23 for a man, under 18 for a woman) it could be hormone and growth related.
I have not seen it proven, but I have this personal theory that although women stop growing taller after aged 16 or so, there is a huge hormonal shift that occurs around 21-22, and I think it can affect weight. But thats just my theory.
You gotta keep on the doctors because its a serious issue.
yes, i even have a frined who has that type of problem.. its normal..
As far as the weight-loss goes...it could be due to the stress of having the panic attacks. You may be eating less and not realizing it. Have you talked to your doctor about it?
And as far as the minimal daily changes go, live4fitness is right. That's nothing to be concerned about it. It's normal.
On the weight changes. You weight more at night due to eating through out the day and less in the am due to fasting as you have slept. and from day to day you can retain fluid.