You get depressed because you regret not approaching her and introducing yourself--it was a lost opportunity. Your brain then ponders numerous "what if" scenarios throughout the day and that can lead to depression. Solution--go up to the stunning girl and say hello. You may get rejected. It hurts for about 1-2 mins, then afterwards you quickly forget it. The upside is that you took the chance.
He has often been called the "Last of the Romans"
"We have prostitutes for our pleasure, concubines for our health, and wives to bear us lawful offspring."--Demosthenes (384–322 BC), Red Pill Greek Statesman