How to be less cynical?

I don't even know if it's inherent but I think that my stupidity and environment have shaped my cynicism since I grew hatred towards my parents when I was about 9 (although we have recently reconciled) and I had an unhappy adolescent year due to academic stress and mental/emotional torture from various extremely jealous a**holes. My high standards also contributed to it. I had lived with it for a long time but the unhappiness grew apparent mainly due to my poor academic performance, a by-product of laziness and peer (enemies) pressure.
Turns out that I have mdd (depression), ocd, add (adhd-inattentive) and gad (anxiety). I guess somehow my unhealthy childhood and teenage years + own high standards + hate to be looked down esp by enemies beat me up into a sorry sight. Messy.
A few adults say I'm smart but wasted. Some said my thinking is mature but a lack of experience makes me clueless with my life. I guess that implies I am a weak problem solver?
When I analyse things, I tend to get on the negative side first. I am currently trying to look more on the positive side first although my previous negative predictions were usually right. Perhaps too much disappointments to me?
Teach me how to get out of my dark ages, will you? I feel like I have created a maze for and trapped myself in it.