Working during the 1st trimester

I'm not a lazy person by any means, I have never not had a job since I was 15 years old. I have been employed as long as I've been able to be. But goodness, I'm having a very hard time working right now. I'm in the beginning of my first trimester. It sounds selfish, I know. But I'm just so tired all the time.. And I never feel good. Do most women work during the beginning of their pregnancy?