Stressing out

I’m stressing about finances. We are 25 years old, so just getting started with our jobs out of college and saving and whatnot. We also have 3 kids and are on one main income (I only make ~$720/month, so we live off of my husbands income). We decided to try for our 3rd baby after looking into our insurance and figuring out how much it would cost us to have her. We were comfortable with it, so we went ahead and TTC. Fast forward, we paid the medical bills BUT... my car is now in need of a major service. $2500 bill. We are still renting a house that is so small and only has 1 bathroom, which is tough for a family of 5. Obviously our savings took a decent sized hit between medical bills and the car bill. We only have ~$19k saved now, and our goal is to buy a house (~$300k) in around 3 years (the area we live in is expensive, which is why the price point needs to be what it is). I feel like we are never going to be able to save enough for a down payment and my anxiety is out of control.