Whats wrong with me!! Plz help?

Sometimes being too much sensitive can depress you i too have a problem my problem is that i get confused and depressed easily usually when i choose things like a subject at school after i change my mind and then i become so depressed that i make it look like the end of the world !This is the way i am and most of the times i become a problem to my parents!This is how people are and i have realized that the only way to overcome it ,it's by willing to get rid of it so whenever you feel like this think if it is important for you to be sad,then tell urself that u are going to be happy coz you want to be like that the think or do something you like !Slowly by slowly this habit will be gone but that doesn't mean u would be always happy u must also know tha sometimes you must cry to free urself !GOOD LUCK MY FRIEND hope i get rid of my problem too !