How do you do it?

I’m 12 weeks, I have a 3 year old ( who has behavioral and developmental delay) also a 5 year old. And I’ve always been a single mom and if it wasn’t for my own mother helping me I don’t know if I would have made it. She’s been the only person who has ever helped me with my kids. I found a man who took them in but he is a RN and works the night shift and is only home 3 hours a day: I’m panicking how am I gonna do this: my 3 year old will be in ore school. My 5 year old in elementary school and then. Newborn?! How am I gonna do this I literally don’t understand how this is gonna work and I’m gonna go in full panic. And he wants me to try to work too.. someone please tell me how you do it.