2 pounds weight gain ...is tht possible ?

You are very thin, and I wouldn't worry about two pounds. You can lose or gain up to five lbs simply in water weight. If you were retaining water for some reason that could be it. This can come from eating salty foods or being on your period, just to name a couple. Also, have you been working out anymore? Muscle weighs a lot more than fat, so if you gained even a little muscle, it would cause you to gain a few pounds.