My husband is leaving me, what do I do now?

TL,DR; I was a stay-at home mom and now I am going to be a single mom to three kids. Help!

On Monday, my husband informed me that he wanted to leave. At first he told me that it was not over, but by the end of the day, he said it was. He is leaving on Friday. I have been a stay-at-home mother for four years. We have three children. I am not looking for relationship advice, I think our marriage is over for good. (Can not afford a lawyer at this time and we have agreed to postpone a dissolution of our marriage for a few months at least.)

I am at a loss at what I should do now. I have not worked for four years, I was a dedicated stay at home mother. (But not what he wanted or up to his standards which he refused to even tell me he had a problem with until Monday.) I lack any real job experience and I do not have a degree. I was planning to go back to school in January, but I do no think that is possible now.

I have applied to the nearest fast food places and retail stores, but I am not having any luck even for seasonal work. The only good thing, money-wise, is that he agreed to pay out the rest of the lease on our apartment. I do not know if I can 100% depend on that though. I have no idea how I am going to be able to pay for daycare and work or if I will ever be able to go back to school again.

Please, any advice would help right now.

EDIT: I'm sorry for taking so long to respond to everyone, yesterday and today were very long and busy days. I have found one good job prospect in the meantime.