When I start to regret things, I make myself do the time travel movie run down... if I'd changed X, then maybe I never would have been able to Y. If no B, then probably no C. Our mistakes are hard to look back on, but who knows who we'd be without them.
I get the melancholy. But I think you're right to focus on the future. Good work so far.
"When your life becomes shattered, you have no choice but to become more of what you are." (heard on the radio)