Re: too much resentment
It sounds like your family acts rather toxic towards you. They use you when they need to, they ignore you when they don't. Until you're living on your own and are financially independent, I'm not sure there is much you can do to avoid resenting them. I think they shouldn't be getting a free pass to treat you poorly because they're family.
I know it's easier said than done, but my advice is to direct your focus and energy towards becoming a fully independent adult. Once you've achieved this, you'll have a lot more control over when or if you interact with them. If they continue to treat you poorly, I say cut all ties with them until they change. This may sound harsh, but as I said earlier, being family doesn't give them the right to treat you badly.
If it's feasible, I suggest putting some distance between you and your family when you go to college. If you can do this, I think you'll find it much easier to put the hate and resentment to the side and focus on taking care of yourself and work towards your own priorities in life. Putting aside your hate and resentment should be done for your benefit and not theirs. Even though the feelings are not unjustified, I'm sure you don't want to turn into an angry and bitter person. In addition, continually harboring such feelings may distract you from focusing on what is really important to you.