Learn everything you can on personal finance. Here are some suggested goals (I'm a former HS financial literacy teacher so I have had plenty of these scenarios brought to me)

1. Try and work as many jobs as you can. Enter your school's work half-day program (it may be called something else at your school).
2. Do not spend any money on anything unnecessary. Suck it up as long as you can and see how much your dad can still cover. Don't party and don't waste any spending.
3. Understand that your girlfriend is just that and not a wife. She may not be your girlfriend next year. You need to focus on how you can support yourself for now and not someone else. Please try to not get her pregnant.
4. Get on a written budget and be as strict as possible with it. Be disciplined here.
5. Ask for help from your teachers and counselors that you trust to see if they have extra resources available for you.
6. Try to get a better job if possible or start a side hustle. Grass-cutting and pressure-washing (and similar) companies are always looking to hire hungry and motivated kids.
7. Using your network, see if there are any low-rent apartments or shared-room situations to lower your rent as low as possible. This will be your biggest cost.

This is not for the faint of heart. I hope you know what you are getting into. You will be sacrificing all of your social life and more to do this but it can be done.