Perhaps every decision you've made up to this point has been wrong. Perhaps everything that has happened in your life could have been avoided. Perhaps your life could be completely different if you had just done one little thing differently 7 and a half years ago. Perhaps. But don't get hung up on the possibilities that have passed and the opportunities that have come and gone. Focus on the future, and focus on the outcomes that you do have control over. Trying to analyze every variable and detail will do nothing but lead to worry and doubt.
Perhaps you should stop looking behind you in only negative ways. Perhaps it's time to choose to live a life with your energy directed towards improvement and happiness. Sort out your priorities, and find the ways you can accomplish the could have, should have, would haves. Life can be random, and there are some forces that are out of our control and will always be out of our control. However, there are other paths in life that we do have the power to alter, so long as we are willing and dedicated to it. Make the decisions you need to make, and put in the work that is necessary.
Don’t dwell on the past.
Focus on the future.