I can relate to a lot of what you said. I've gone through many times of feeling very burned out. I'm kind of going through one now.
It's exhausting, some days I feel like I've got nothing left in me to do this another day. My temper is short. Actually, now that I'm thinking about it, there basically is just one child causing these feelings.
When she isn't here, life is good.
Is there some other change you could make to your daycare that might help? I know you've changed your room around, cut back your hours a bit. Do you belong to a support group for providers? Are there any fun classes locally you could sign up for, whether daycare related or not? Have coffee with a friend and use her as a sounding board; make sure you return the favor.
Sometimes it just helps to unload on someone or brainstorm with local provider friends.
Do something for just you. Join a group that you're interested in. Check out to see if there are any meetup groups in your area. Set aside a few of your hard-earned dollars every week and save for something special, for you.
I just reread your post where you're too tired at night to talk or be with anyone other than dh. Take advantage of your weekends. My nights consist of taking my dogs outside, being on the computer and reading. It's stress-free and quiet, 2 things that help me unwind from today and prepare for tomorrow.
Good luck and hope these feelings pass soon to get your through the next year.