I think your question needs to be asked in a different section for more of a response from others.
Just ask a moderator if they can place in a more appropriate area.
i congrtulate you on making it thus far without a studen loan, but in order to move forward you may need help,. Go a head and feel out your FASFA and borrow what you need until you get on your feet. It may be only a temporary solution before you get any further behind on your car an credit cards.
+1 on the student loans. You can easily get enough to pay off your relatively low debt. You do not have to start paying back any of the student loans until six months after you graduate, but you can pay on them whenever you want. It is definitely very responsible of you to put 20% away in savings. I think that you can easily cut that down to 15% and take the other 5% and put it towards the repayment of your student loans, or, leave it at 20% and put 5% or so towards the loan repayment. Then, start building positive credit with a cc, secured or unsecured -- it doesn't matter; whichever you can get approved for. But know what your scores are at before you apply for anything so that you do not waste a HP on something that you will probably be denied for.
Can you find an additional job? I would try that to bring in some additional income to help pay your bills. Other than that I would create a budget and stick to that of course. pay the minimum on your bills but throw any extra money you have first at an emergency savings account to cover things like flat tires etc. and then start attacking your cc debt. I would also try asking your sister for repayment. She should understand your situation and maybe she can start making payments to you. I wouldn't depend on anyone but yourself though and I am speaking from experience.
Join the Reserves !!!! Im serious