I agree with paddyd, it seems like an awful lot of strain. Are there any other options. Without a car, you are really putting huge stress on yourself twice daily, and an enormous commute.
You will be so tired and stressed, you will be literally working, sleeping and nothing inbetween.
Coudl you get a job in Kilkenny, surely even if it were alot less money you would make savings from all you would be spending on public trasport. Or else maybe rent in Dublin for the short term, and apply for jobs at home.
I think it would be no harm to look at all your options and think about the bigger picture.
Is there anyone in Dublin you could stay with (friends?) in the short term until you sort yourself out?
best of luck with it all, sounds like you've some hard decisions to make.