I speak to you today as someone who did two majors at the same time while also home schooling, being active in my church, and running a small business. How did I keep things straight? By using a calendar the way in which I am about to share.
Purchase an academic calendar at an office supply company- get one that has an entire month at a glance. As soon as you get your syllabi from your various professors, enter all assignments (including reading and labs) in your calendar. Use a different color ink for each class. When you have a major assignment due, highlight it in yellow ink.
Next, enter all family and work obligations in the calendar in a different color ink. Your family needs to have some time set aside for them, so you do need to put them in your calendar, as well.
While some people insist that their cellphone will tell them when something is due, this method never crashes, is never out of cellphone range, and does not require electricity. Yes, it is old-fashioned, but, if you look at the calendar on a daily basis, you will never be caught off guard by an assignment. I would check each assignment off as I did it, being careful not to obscure the assignment itself, in case I needed to refer back to it.
This method got me through 5 years of undergraduate work, 1 1/2 years of master’s degree efforts, and five years for a Ph.D. I only missed one assignment once- and that is because I left the assignment off of my calendar. I now teach for three colleges and guess how I keep track of which week each college is in and what is due from my students? Right, my friend, the calendar!