Share your problems with a real person close to you. Tell them about your sleep patterns, they'll try their best to help you and your sleep routine.
Your 16, thats the stage to feel the way your feeling, its normal dear, just that not all souls are brave like you to speak it out. you wanna know what your life is all about? Well, here's some good and bad news. The good news is life has no defined path, you get to choose what you do with your life, there's more than a trillion choices you can choose from, you can choose to be who you want to be,what you want to do, and that's the first step. The second step after choosing what you wanna do, focus on that, give it your whole and best shot. When you do that, you will realize that you don't need anyone to show you they care about you, those who care will do care. You will have enough sleep after you get tired of doing what your focused on. Sleep comes from a tired body not over thinking. And the bad news is , no one gonna find your life purpose, it's just you and yourself. Wish you luck.