Hi Sonia,
I tried it and nothing happened. I'm petite, too. I wasn't loopy (maybe really slightly) but I wasn't hungry either. At the most it felt like I didn't get that full feeling as quickly, but it didn't really make me feel the need to eat. I didn't give it weeks, though - so if you try it and find it works after taking it some time, let us know!!
After that, I tried Megace and loved it. But, like you, I gained a lot of weight quick and then it seemed to level off. I haven't been on it since though, since it seemed to mess with my blood sugars. But I loved not having my period! lol
Kris
26 w/ CF