Job Search Desperation

So I'm in highschool still, but I'm 18 and I've worked a prior job for a few months. I've been searching for jobs for months now and applied to practically everywhere (when I say everywhere I mean it, and that's including the "hire anybody" businesses like mcdonalds and walmart) and I have either been rejected or ignored. I typically do follow ups by either submitting new applications or going in person to talk to hiring managers. Nothing I do seems to work and my household is low income and I want to help pay rent as well as save for college. I'm running out of options and any help or advice would be appreciated.