Solo Q Help

I need help in Solo Q. Regardless of how I do, I keep on losing. I started off in Silver 1 now I'm all the way in Silver 5. I'm pretty sure I'll be in bronze in no time. Even when I do great, there's someone on my team feeding every game. I don't understand how am I suppose to win? I've been positive in games as much as I can, but in the end I still lose. It makes me almost mad because I want to do good, but every game there's a major feeder on my team. Sometimes I even have bot lanes giving doubles before 3 minutes... I don't even get what to do. Some of my losses are my fault for sure and I accept that, but not all of them. Most of them, are a team loss, and I just don't get how to win. Please help me out!