mm, I really don't think that u're "too thin" I suggest you visit different boutiques and actually try on lehnga's, fishnets, mermaids, farshi gharara, regular gharara, sharara's etc and see what suits u're frame.
I blv a heavy "ghair" wala gharara wud look great paired with a slightly longer kameez (perhaps one that reaches u're mid-thigh's)
Wear short sleeves so u can show-off u're mehndi, bangles and bazuband (if any)