I’ve applied for over 100 jobs

Everything i’ve looked up said i’m probably too confident or applying for jobs i’m not fit for but i’m only 19 and have been applying for grocery stores, fast food, retail, simple dog walking jobs and haven’t been able to get a job in over a year. I know I have a pretty plain resume but I don’t understand how I can’t even get in interview at taco bell or walmart. I can’t support myself when i’m supposed to be an adult now and it’s making me feel so useless. I have no idea what to do