How can I build my smarts + self esteem to believe that I can do something that is more fulfilling to myself?.?

I need a better job. I only make 306 or less a month with the job that I have. I haven't been able to find another job because of the way this job is scheduled. If I do find another job they want someone to fill the position as soon as possible and I am afraid to quite my 5 year long job. Give a two weeks resignation letter. They usually find someone who is unemployed and who can work immediately. My self esteem sucks and I think working sucks in general. Time is running out and I don't know how I am going to support myself. I should be a professional tenor but too much money is going into investing in voice lessons. Competition is plenty. Feeling down. Situation feels complicated./ complex. What career should I change it to? Back to a school that I can not afford. I may have bad credit at the end if I can't find a job.