You are not alone, I often feel the same way. I wonder on weekly basis whether my life could of been more, more than what it is. I think it is human nature to reflect and question the choices we have made. Everyday is an opportunity to choose differently, to do something more. I am currently working on changing my life for the better, making small decisions daily, hoping that they will all add up to something great. So, stop thinking about what coud of been and focus on what you can do now.

Hopes this helps.