I recently hit Gold playing Support Solo
Now usually a lot of people at Bronze/Silver would tell you not to play support or play an AP carry support so you can carry. Supports don't generally carry in the traditional sense of "I'm going to build lots of damage and kill stuff" but they're actually quite vital to team play.
This season I managed to climb from Bronze III to Gold V playing solo support for about 80% of my games did I get a little help? Sure but to be honest I didnt really win much from groups. But climbing from Bronze to Gold by yourself isn't really impossible it just requires a large amount of patience if anything.
So for any of you solo support in Bronze / Silver are stuck don't worry If you continue to play well you'll eventually climb, If I can do it so can you.