I see a few comments telling you that your daughter will be in preschool or Kindergarten at 5 but I know that does little to help your situation now. But (not sure if it depends on your state) she might actually qualify before then. There are usually programs to help out for poorer families and single parents. These cases often get priority in preschool.

Another option, depending on how you feel about religion, is church sponsored preschool/daycare programs. They're often cheaper than regular daycare. Even if you're not too fond of the religious aspects it my ease your financial burden until she's able to start public school.

As a single father myself, I understand some of your struggles, especially with the financial burden of daycare. I will say that I think your fears of not being good enough for her are a good sign and I think every "good" parent experiences that. If you choose to stick with it and power through these hard times, I promise you she will give you the greatest moments of your life. Watching her grow up will make all these hardships worth it in the end. As parents we get caught up in wondering if we provide enough for our children when all they really want from us is our love.

If you ever have any questions or need to talk, don't hesitate to message me!