Most of us are parents, and we've juggled school and/ or work with family obligations. When people have difficulty doing so, it's usually because of not studying effectively. The best thing you can do is schedule separate time for studying, for being with your kids, and doing other things. Then stick to that plan. You're not doing your kids a favor, or your school work a favor by letting the other distract you. If you're sitting at your desk and turning every 5 minutes to talk to your kids, you're not really absorbing the information. If you're playing with the kids and you keep pulling out your flash cards, you're not giving the kids your undivided attention.
Figure out how much time you need, then devote a block of time to studying each day; if you have to, go to a library so you're not pulled in another direction. Don't take your phone (or at least put it on silent and put it out of sight). Don't check emails. Don't log onto Facebook. Devote the time to studying. And, be organized about it. Break down the work into chapters, or diseases, or systems and focus on ONE thing at a time before you go on. Take notes, write flashcards, or whatever you find to be helpful. Be systematic and organized. When time is up, go back home and spend time with your kids... and don't be tempted to read over your notes. This way, you'll devote yourself to your kids 100% and you'll feel less guilty when you have to study.
Think about it this way, when you finish school and you're actually working, you'll have to be away for 8+ hours each day. School can be a bit less of a time demand, but you still have to devote uninterrupted time to studying and classes. Deal with school like it's a job, not like it's an option.