Maybe some small, practical steps will help.

What about the boy's paternal grandparents. Could they babysit one weekend a month or every two months. It would give you some time to yourself.

It sounds like you may be over-tired. Could someone babysit while you sleep in, get a manicure, do some self-care?

Think about help and nutrition. Omega 3s from flax oil and fish. Leafy greens.

When you finish school you will be less stressed and you may even start enjoying the kid.