KayAnn:
Please don't feel that there is anything wrong with you. Just ask Simba, who loves you so much, and he'll tell you that you are a wonderful person. You are going through a very stressing time and it's only natural to be depressed. It's hard enough to be your age without having to cope, at the same time, with all your other problems.
As other Pet Talkers wrote, try to find somebody you trust and can talk to. We are all here for you, but you also need to get help close to home.
It's very frustrating to see the people we love in pain, but perhaps a way to help your dad, and yourself, would be to tell him how much you care for him and how well you understand his suffering.
We wish you didn't have to go through all of this and hope you will find a way of bringing out your feelings of frustration by talking to a counselor, or anybody else with the experience to help you.
You'll be in our thoughts.