I feel depressed these days?

Recently, I've always felt depressed. Yesterday my mom started to get mad at me cause I told her I didn't wanna talk! I know why I feel depressed. I feel like I'm wasting life. I'm only 15 I just turned 15 and I feel like I need to have something that I'm good at. For example, this dude in my class is planning to be in the NHL and played hockey around in Europe and he and someother kid got chosen to be the two players for Canada. He's going to play hockey all summer and he loves doing it! This other girl I a great singer. She sang for the last day of school and I got goosebumps and everything. I feel like I'm the only one that has nothing I'm good at. One time i tied with all my effort to draw, and I couldn't so I let go of it. Then I realized that recently I really wanted to act. I keep watching movies an tv shows and I wanted to be them. I posted questions about it. But I figured that if my teacher didn't like my audition, I can't do it. I decided to let go of it. But I can't let go it! I enjoyed that time where I had to keep reading my monologue over and over. I enjoyed watching people do this monologue and getting tricks. I enjoyed this so I couldn't let go if it. It's still on my mind. I listed a few books but I didn't get them yet. I'm trying real hard to let go of it cause I'm not good but I can't. Same goes with singing. I feel the songs but I can't sing. Heck I have a flat voice so it's even disturbing when I talk! I've these dreams where I sing on YouTube and manager finds me and I get signed. I've also these dreams where I do a monologue on YouTube and an actor finds me and I get signed. How can I stop this and focus on just enjoying life for now? I really wanna act but my teachers the drama teacher I think he knows best.