No time for regrets, because no matter what, you can't bring back yesterday, it's GONE!! The past is over, we can't hold onto what's been done but move ahead.
It's best to just be alone. Stop hurting feeling miserable too much too handle .. Just throw yourself into a project or something.
Sometimes the past could be the best once again...moving foward is not always the solution and it doesn't mean automatically you gonna be hapy just because you were stressed at the past....being patient can be helpfull sometimes.