Problems!!! Help Me understand!?

I dont know if it is bad luck, karma or what other term there is, i have been having so many problems. First, I find out i have depression, and anxiety (therapist) and I was only 9 at the time. I hardly want to get up out of my bed and I see really no point in life. I dont remember a time that I was ever happy for more than a few minutes. The day of my graduation, I laughed with my friends and had so much fun, then I chipped my tooth from laughing. First day of middle school I was so excited and energetic, I went to the pool, and I pulled my back muscle, only a year after pulling my stomach muscle.I get a loose tooth every month, and I always have to eat on one side.(i have a lot of dental problems). More situations I couldn't remember...... Fast forward to the end of 6th grade, I was happy and smiling, then I find out my counselor wont be coming back next year, and she was the only person I could talk to. It was only one week since vacation and I WAS relaxed and having fun for a short while. Until a small chip of my tooth came loose and I couldn't eat. Every thing fun has to end in something bad happening for me. My first time on a fun roller coaster, I got extremely nausiated and I almost passed out. On my 10th birthday, my cake got ruined on the way. And, I am only 11 going on 12. I just need help understanding life. For some, they get family members killed, they get illnesses and terrible things occuring. For some they get a much better life. And so many innocent people get killed for no good reason. I think of myself as a nice person. I dont harm, I dont like making people feel bad, and I am the person who does what they are told, and then I am mocked and called a goody-goody. What did I ever do wrong? Or does life just suck like that.