Reminds me of my grad school days, when I was working three jobs and also taking classes. Proud to have done it, glad to be done with it!
One thing I did at that time was to keep a very detailed time diary for a typical week, much as MMM encourages tracking expenses in the early days of Mustachianism. Helped me find a few places I could be more efficient and also reassured me that I was using most of my time well.
Another thing that I have found to be very helpful is creating routines to handle a lot of the ongoing chores of life, which frees up brain space for all that other work you are doing. So for instance, keep a running grocery list through the week, and then Tuesday afternoons is grocery time. Wednesday morning is laundry day, or whatever. An old-fashioned way of handling groceries/meals is to have a weekly menu--ie, Monday is breakfast for dinner night. Tuesday is pasta w. sauce and meatballs night. Wednesday is grilled cheese sandwich and tomato soup night. A little boring, yes, but you are in survival mode here. When I was in the crazy grad school years, I also planned leisure time into the routine. 10 PM Saturday night to 10 AM Sunday morning was my Sabbath (I am Christian, but the principle applies even if you aren't religious). Later when I got a fellowship and dropped some of the jobs, I stretched it to 6 PM-noon. Having that time to relax, guilt-free, was really helpful keeping up the pace the other 6.5 days per week.
I recently came across the to-do app/website Workflowy which has worked very well for me. It is free until you surpass 250 to-do items in a month.