Down and depressed

I am currently 7 weeks pregnant and I’ve never felt more depressed in my life. I have Two other kids aged 15 and 4. I was not planning on this one and it has hit me hard. Is this normal? I know that I am “lucky” to be able to get pregnant but I don’t see it that way right now. I wanted to start living my life and now I know this is gonna set me back😭. No negative comments please🙏🏼