Hi GC80, welcome to PsychCentral (PC).

I don't know that you can live your own life and your mother's? I would try to think of a whole lot of scenarios and see if you could put some of each in place and then escape and use the various pieces to help.

How about talking to the family doctor? Could s/he somehow help some with either advice to you or ideas of how you could have people check in on your family if you were not there?

Could you get a better paying job somewhere else and send back money? Maybe your mother would not be quite as unhappy if there were more money?

Could you go to school (or work) that required residence some/most of the time and get your mother use to a slightly different schedule/seeing you less often?

Could you find a duplex flat/houses somewhere and arrange so you could live close/next door to your family but have more of your own space?

Can you take up a hobby/job that takes you away from the mess of your family longer or allows you to be doing something you enjoy on your own?

It sounds like you might have to either get far enough away that you were truly away or ease yourself away bit by bit? Figure out a scenario where your sister could visit you if you got a flat/new place to live so your mother can't use the argument about your being late upsetting her or perhaps your father could live with your part-time so it frees your mother of being near him? Figure out a scenario where your mother could come visit you on her own so she gets some time away from her worries and your dad (someone to sit with your sister/father).

Make sure you see what is "real" versus your mother's version of reality? Does your sister really get upset? Are there other ways you could comfort your mother or help her with her anxieties and difficulties? Can you get other friends' mothers to take your mother under their wing or get her to go out with your to church or civic events and get to know/enjoy some other people so she is not so dependent on you?

I think I'd also be tempted to point out my own individual needs to your mother in the same language she uses so she can experience what it feels like or how others see it; tell her you one may be sticking a knife in her if you leave but she's sticking a knife in you by smothering you in this way and see if you can get in a good discussion where the two of you come up with a way to make the two of you happier instead of just one or the other of you?