I need someone’s advice

So we got a letter from our apartment saying that we have leave by December 7 or otherwise they will put our stuff out of the building. Because They are saying we own them 1,338$ on rent, and when we call and talk to them they said that the rent went up and we weren’t paying the whole rent complete...we didn’t know that. Now we don’t have that kinda of money to pay and also we don’t have a place to go. We applied for an apartment long ago and we are just waiting on them. I need someone’s advice or help. Or ideas I have a baby who is 8 months and I’m pregnant with my second baby. And I’m not working only my boyfriend. So also I want a job where I don’t have to put my baby on a daycare cause is going to be more expensive. Please someone advise.