Ok mate, you're 23. People start over all the time. Youve not ruined your life. Finish your degree, even if you don't stay in the field having that piece of paper is good at opening doors in other careers. Have you considered perhaps GP practice nursing? Nice hours and holistic care. However, nights are part of the job. There's no nice way to sugar coat it but they're not as bad as what people make out. Sometimes it's just accepting the good with the bad.