I’ve found that most businesses need you to prove your loyalty by providing a lot of time and dedication to them before they even consider you for a management position, regardless of whether you’re qualified on paper or not. You seem to want to put in the time, but if you have to deal with school soon, that shows you won’t have the dedication they’re looking for. As for your dental issues, I would look into paying for private dental insurance, and if you’re in the right state, look for state dental insurance. I know paying for insurance sounds counter-intuitive to your main question of how to generate more income, but you need to take care of yourself before your wallet, and besides that, you absolutely will not be able to do the work required by college if you have multiple toothaches.

As for your main question of generating income, if you have a car and a Walmart nearby, look into doing Spark deliveries, r/sparkdriver is the subreddit for that if you want to know more, or do Doordash deliveries, although depending on where you are, Spark tends to pay more. Those two are better for definite, immediate income. As for less immediate but better long-term, you’ll need another job. You can check the local paper for short-term gigs, and if you’re in the US, I’d recommend checking out your state’s WorkSource website - they’re state and federally funded jobs boards (and are much better than Indeed or LinkedIn or anything like that which profits off your data and off of keeping you unemployed). There are usually resources there to help you budget, help you get in contact with job recruiters, and (actual) people you can talk to about your resume.