I don’t know how to feel

I’ve recently found out I’m pregnant. Got my positive test 2 days ago. I’m 4 weeks. We were trying for our third and final baby and was so excited and now it’s happened I just feel overwhelmed and sad, I keep crying and had a panic attack in the bathroom earlier and nobody knew, I feel like I’ve made the wrong choice and I don’t know what’s wrong with me. I keep thinking is this fair on our other children, will we manage, will we manage financially, my partner expects me to do most of the things with the children developmentally and the pressure of another is making me worried. I had to do every single feed with our second and I’m worried I’ll have to do the same again because he won’t and I was so drained. I don’t know what to do. How hard is going from 2-3 really? I was just so excited to get pregnant and this isn’t how I want to feel 💔