Heather, I’m going to assume you submitted VA Form 22-1990 telling the VA you were starting a new program. They need this form to match up with the one your school sends in once you are enrolled to get your Montgomery GI Bill payments restarted. If you have not submitted the form, then you will need to do so as soon as possible.
It normally takes about 8 to 10 weeks before you start seeing any money. After you get your first check, then you should see a monthly amount shortly after the beginning of each month.
Because of the lag time in getting the first check, I always advise students to have at least 3 months of funds in reserve to cover their bills during the initial period. If you don’t have that reserve, and it sounds as though you don’t, then you know it can get rough while you are waiting on your GI Bill payment.