Fucked up

i’ve always felt abnormal .Now i am 18,and i still do. I think i have bipolar disoder,body dismorfic disorder and depression.thats not a good way to “start” my adult life.even though i am miserable inside,my parents an twin brother dont suspect about it.I’m pretty sure it is beacause i try my best to look normal.well,i am fucking tired to pretend all the time.I am fucked up!I know that i should just tell them what i feel,but i cant do it.So i feel trapted in my onw head.Suffering alone.