Understanding husband

Ive been so mean recently snapping and yelling at my husband for little stuff that really isnt his fault and instead of him snapping back as he would do if i wasnt pregnant he just says 'baby calm down' or ' are you okay'... So today i fussed so much that i felt bad so while he was out picking up food i messaged him to apologize and he says ' hunny its ok i know your tired and uncomfortable' im so grateful for him