HELP! mum wants me to gain weight?

over the past six months, i have lost a considerable amount of weight.i weigh 94 lbs and i am 5 foot 4, my mum wants me to put on half a stone to a stone. Before the weight loss i was 112 lbs, and i was miserable. I didn't have a flat stomach and i wasn't overweight but i feel so much more comfortable this way, if a little skinny. But i don't want to gain weight as it will all be flab! i am petrified to gain fat, as i do have some, i'm not skeletal. I haven't had my period for a while but i am certain once my body becomes accustomed to my new weight they will return. what should i do? help please!