You can’t undo things. But hopefully you learned something from this situation. First, do not “lend” money you cannot afford to lose. Second, you can always say “NO”. Third, lending your co-worker money does not make one a team player and doesn’t really foster camaraderie. Fourth, keep you boss out of your personal issues. I know that your co-worker borrowed money at the work place-----but you were a consenting adult, so I don’t believe that that kind of thing should be reported to her.