Maternity leave

Okay so I’m due to go on maternity leave in April when I’m 37 weeks. I’m only 24 weeks currently, I work full time 40 hrs a week sometimes more which if I wasn’t pregnant it wouldn’t bother me but most recently as of a few weeks ago my body has not been allowing me to be able to work 3 out of the 5 days. It’s those days when I wake up and feel like I’ve been hit by a bus and no matter what I do nothing helps besides rest. I also have GD, I have those days more often than not. So my question is do you think my doctor would write me a note to go on Early Maternity Leave if I explain to her how I’m feeling?