Need help with my weight...?

Ok im `female,19, 5'2" and the last time i went to the doctor the scale said i weighed something like 155lbs (my weight is usually between 145-160, im ok with the way i look now and i wouldn't mind loosing at least 5 pounds but i don't want to be too skinny or get too fat. when i was in weight watchers i lost 14 lbs and i was skinny but not anorexic skinny, more like a toned/hour gl fig. kind of, but i didn't like not having anything for anyone to look at, i had a huge and thighs and when i lost weight i lost my /thighs and i felt bad because that's the only thing i have that makes me look good). Is that good or bad for someone like me? Also, my mom (who has dieted and exercised her whole life and wears size 4 pants) is always telling me i'm fat and that i need to lose weight she's always saying stuff like "you need to lose 5 more pounds...10 more pounds...my god your fat you need to lose 20, you have a bathing suit that you need to be able to get into and look good in this summer!" and whenever we go to the grocery store she makes a scence and says "my god, this is embaring everytime we come in here we are bigger than we were the last time!" It's like she can never say i look good no matter how much weight i try to lose or how good i think i look (one time when i was 15 she made me join weight watchers and my mom tried to get me to weigh less than 100 lbs!!) i've even thought about making myself vomit so i could finally be skinny enough to make her happy, but i don't know if i can make myself go through with that. so what should i do about my weight, should i eat less and constantly depend on seeing and maintaining a certain number range on the scales just to make me happy (which by the way i heard is bad for you or something) or should i just try to eat right and exercise and drink a lot of water? Help me what should i do!?