Working mom guilt

Because of current circumstances for my family, I'm only going to be able to take 3 (maybe 4 weeks tops) off when baby is born in December. I've always planned on being a working mom, since I was little, but yesterday I just started feeling so guilty about it - and she's not even born yet so I know it's only going to get worse!

I'm a ftm so I've never dealt with this before - how do you working moms work through this?

Edit: unfortunately, as a teacher, my days and hours are pretty set and going to part time isn't an option.