Yes, once you do what you need to do to trust yourself once again, you will feel positive things, and think positively. You're currently feeling negatively ("m

Yes, once you do what you need to do to trust yourself once again, you will feel positive things, and think positively. You're currently feeling negatively ("miserable") and thinking negatively ("I am no longer young"). That is fine. [Do that, it's a healthy experience!] You'll probably want to simultaneously take care of your body and mind, while you are feeling negative. That way your physical experience of Life can be positive. If you are having unsatisfactory difficulties recovering, get a Licensed counselor to ask you self-reflective questions. That can un-stuck you. Congratulations on having a start-up of your own, sincerely.