When my kids were small I had some stay at home years, some part-time working years and some full time plus going to college years.
One day when my youngest ( @6 years old) heard I was taking another new class- he frowned and I _did_ feel bad but then I remembered that I was working on my degree so that I could make a better income for my family's benefit.
You are to be commended for doing such hard work and I'm sorry it's so rough on you in addition to what's going on with your husband right now.
My advice? Uh-oh...I'm supposed to limit my sharing my experience, strength and hope. lol When stressed I try to remember to take good care of myself by eating right, getting the rest I need etc etc. It's a good recovery tool- self care.
btw Feeling guilty never helped me to be a better mom or a better anything.
I hope you can squeeze in some time to rest and regroup, even if for short periods.
Your baby is fortunate to have such a hard working mom.