Depressed?

It has been months and months in which I have been seriously contemplating whether or not I am depressed. Some days I will smile up at heaven (this not intended to start a religious battle, but for all educational purposes) and thank God for all he has done for me, however other days which seems to be a 70% time thing as opposed to a 30% time of the looking to heaven. I feel extremely stressed due to school, I am 16 years old have been taking classes since freshman year (now a junior) throughout the high school years with not a single summer break. Now I realize that there are people out there that have taken classes for far more years with no breaks, but it just feels overwhelming. I let my parents down, for I don’t try my hardest in class, I never study, still manage to get B’s. Nevertheless, I feel like it is not good enough for my parents, even though they are proud of me for dual enrolling (take classes at a nearby college which gives college credits and high school credits). I am constantly having to do work for my online classes and my typical enrolled classes. I have friends that I talk to most days, but they don’t feel like friends I can tell these type of things. Honestly, the only reason I am doing this right now is because I don’t know what else to do. I think of suicide and how it would just make it all go away, but then I think of how my brother would feel and how the rest of my family would feel. I usually begin to leak a few tears at this thought, though it is a frequent one. I have never done self harm, but have come close. I know it will probably end in the response of “Tell someone you trust” but the thing is… I don’t have someone like that, while me and my brother are close it doesn’t seem like the type of thing I can tell him.