I'm 21 years old and at this point with everything going on I'm worried and afraid about life

The situation you are in is very complicated.  As the first born, you likely feel like you are more responsible for the family and I'm sure you have had a role in caretaking for the other four siblings.   It is very tough to see what your siblings are facing, but I know you have also likely faced similar circumstances when you were in the home.   As much as you feel responsible and may feel guilt related to the current status of family members, you are not in a position to financially provide for the family nor is it your responsibility.   I would suggest that you can't own all the family problems and you need to set yourself up for success as well or you may end up in a situation of financial hardship in the future.   I'm not sure where you are reaching out from, but I would suggest that the family seek social assistance from whatever sources are available.   Maybe the family would qualify for some aid or help especially related to the siblings' schooling. 

I know all of this seems very overwhelming, but you have to look at what is plausible for you and play the situation out until the end.  If you go home, what will be the likely outcome?   Would that put you in a position that your life was on hold and your school was on hold?   If you don't complete your school, would that put you in a position where your career chances were largely diminished?   If so, would that make it where you would not be able to have a better financial career and likely place you in the situation where you would have to just work low paying jobs?  What would be the outcome for your mental health?   If you put your mental health under more stress, would that put you in a position where you would not truly be able to even help the situation?  What part of this situation is yours to own and what part is your parents? 

As a child in the family, you are not in the role of having to bear responsibility for all hardships and figure out the solution.  You have helped as much as you can in the past, but you currently do not have the resources to help as you are not working.   Sometimes we jump at the immediate need but box ourselves and our futures in by abandoning the positive steps we are taking to help us in life.  By staying on course educationally, you may be able to provide more support for your siblings down the road.  Your parents may have to figure this out as you have stated you are pretty much having to figure things out on your own.   Just because you are the first born does not mean that you bear the responsibility for the whole family.   Sometimes in life we have to figure out what we can and cannot control.   We also have to figure out what my responsibility is and have personal boundaries.  It is often very difficult, but we sometimes have to accept the things that we have no power or control over in our lives in order to have any peace.   

As this question you have written doesn't include specifics, it is hard to understand all the dynamics of your current situation.   I do encourage you just to play out in your mind whatever choices you have and list all the pros and cons of each decision.   You may also want to spend some time evaluating what your responsibility is in this situation and what you need to do to stay on course in your life, career, and mental health.  Then you can ultimately make the best decision, not just for the immediate term but for the long term.