Being a teenager is one of the hardest things that a person can go through. There are so many conflicting emotions, that some days you don't know where you begin and where you end. Compounded with a lack of support, it can almost feel like you are fighting a losing battle. I am 21, so my teenage years are not too long behind me. I know where you are coming from when you say that you were raised to show no emotion. The same thing happened to me. But you are still young and have time yet to find yourself. Just don't give up. Good things are on the way for you. Talking to a counsellor is a good thing, because then you won't feel like you are going through this alone. You shouldn't be.
I don't know if this will help, but have you ever tried making a list of the good things in your life or the things you like about yourself. Then when you are feeling low, just take it out and read it and then you will know that you have at least something to be happy about.