DH was home with of our kids sick this week and told me I had to watch this segement so that should tell you I've 'been there, done that'.
With that said I got some great advice a few years ago from some mentor mom's who seemed to be balancing family, career goals, and their own needs. Their secret was from a book "Sequencing" that's a few years old now now but the basic concept still holds true--that women in today's society are living in a time in history where we can 'have it all' but NOT ALL AT THE SAME TIME.
I've worked at home when my kids were babies and toddlers (so much harder than it seems to outsiders!), went back to school due to career change and am finishing up my degree while working full time. But it's been a process that didn't all happen at once and I adjusted my plans and time table based on family needs and stages.
I waited til the youngest was in preschool to go back to school and took classes part-time, that gave me time to attend classes and get the work done that was still managable. I found a mother's helper (2 wonderful girls through word of mouth and an ad at the local library) to come regularly and extra help during mid-terms and finals so I could get work and household stuff done. And when my youngest entered school I geared up to full-time class load for my junior year.
DH has also been a huge player in this--like others have pointed out this is a HOUSEHOLD issue and we're a team in this. It's not always ideal and there's been a lot of growing pains but we've got the same goals. As an internship turned into a job we decided together that it was a good investment in our sanity to get some cleaning help (we have a child with asthma so this is a health issue too)--he hates household chores and we realized cleaning help is cheaper than marriage therapy! I've kept my job and it's now my full-time employment so that was a good investment in my career too.
Your specifics are certainly going to be different but the main thing is figure out what's the main priority (in addition to your kids needs) now in this stage of your life--I'd guess school or job. Then scale back, get organized or get help on all the 'non-essentials'. I don't think you should drop out of school all together--it's so hard to start back up. But definately scale back. Also think about taking traditional (not-online courses). The ability to think w/o kids around, have somewhere to go and get out of the house and socialize was a huge plus to my psyche.
Good luck and hang in there!