Pregnancy discrimination

so i handed in a doctors note for not working more than 40 hours a week, for the pregnancy (i usually work a shit ton of overtime). anyways because the note said “please allow our patient to work no more than 40 hours a week” my job took that as a recommendation and not a restriction and made me pull a 16 hour shift the same day. i mean, i feel like this is wrong. they said the note had to say “mikayla can not work more than 40 hours a week”. it’s honestly bull.