I really need to lose weight?

ok when i was 12 to like 15 i had the perfect body. i started to gain in the past two years 20 to 30 pounds which is a lot. i know i will be fine when i lose the weight its just i never actually had to watch my weight so i really don't know what to do. my family is no help my dad makes pasta and rice and fried cheese and is no help cause he's obese and he buys cupcakes and brownies even when i ask him not to cause I' m trying to lose weight. i weigh 170.i am 17 and 5,6. please help i want to feel good about myself again and lose the weigh i need to before it gets out of control