How do I start?

I’m a mom of two preemies who just got home from the NICU after a 5 month stay. One of them is on oxygen at home, needing attention all the time. Though I have a nurse round the clock for her..it’s very difficult for me to leave her side.

My back hurts, I constantly slouch, I need some time to myself or I’ll go crazy.

How do I start exercising!!?