My baby is too impatient

Nursing my son hasn’t really been too difficult, but these last couple of weeks have been really hard. Lately when I nurse him, he starts to wail and scream because he’s not patient enough for a let down or gets frustrated when the let down has passed. I wonder if it’s because I recently went back to work from maternity leave and now he’s used to a bottle? I really hope this passes because it’s really frustrating and I want him to get enough milk.