I taught at a difficult school before and I totally understand how you feel. I was exhausted at the end of each day for about three years.
So, I agree with t_ruth that an Ed.D sounds like a better choice for you because a lot of Ph.D requires you go to school Full-time, and do TA or RA jobs.
Also, is there a specific reason that you want to stay at a difficult school? If you want, I think with your education and experiences, you should be able to find something in the university when you do your Ed.D. It will be more manageable.
Anyway, talk to the Ed.D program and ask for more details (class schedules, requirements, time to reach candidacy, on-campus job opportunities).
Take good care!