Getting a job while my mom has cancer?

I am nineteen years old, and have recently returned to live at home. After graduating high school in MN, I went to college in LA and found myself totally overwhelmed by the new environment. I withdrew into myself, and ultimately took a year-long leave of absence.

Since I've been home, I've failed to get myself a job and my own apartment like I'd planned. I wanted those things in an effort to test myself so I could grow up, but I failed to motivate myself enough, or take the risks involved.

Then, recently, my mother developed breast cancer. She received surgery, but in the upcoming months as she recovers and undergoes chemo, she'll require a lot of care. That falls to me, since I'm constantly at home (I ensure she takes all her pills and does all her exercises, and I empty her drains).

Based on this, I think it doesn't make sense to get a full-time job (though I am currently working with my uncle part-time on a small start-up company). However, I view that as a crucial part of growing up, and I'm already disgusted with how long it's taken me to get on with it.

I'm so sick of living at home and not having any friends (they're all in college), and not having a day-to-day job to take my mind off things.

So what should I do? Try to juggle both a full-time and part-time job, and take care of my mom, or wait for an undetermined amount of time until my mom's recovered (it could be as long as nine months)? Is it selfish to even consider? Or am I copping out if I don't try it? Is it normal to feel like this?

Please help!