CLOSE THE PAST. LIVE IN THE PRESENT. DREAM (or HOPE FOR) THE FUTURE...
Past is past. What's gone, it gone. What's done, it's done. So, learn from the past and close the chapter seal tight. When time requires, you have an option to open it.
Neither can you bring Stone Age back to life, nor can you teleport yourself to another world. All you can do is plan as you go, to survive in the present. So, do what you can do now. That's what living means. That's what living requires.
No one knows what's going to happen tomorrow. May be you will earn a 100 million dollars lottery. Or may be the world will end. Or may be you will meet an Alien from space. No one knows. But, tomorrow is still as important as today. Live today while you prepare for tomorrow. Tomorrow is your desire. It's your hope. Or at least, it's the time your hope may come true.
What's important in life is to believe in yourself. Be yourself. Do what you want to do, what you desire. There are sufficient people in the world who will correct you if you are wrong.