Question ladies,when i pump every 3 hrs i normally get 2-3oz per breast.if i pump after 5hrs,i would…

Question ladies,when i pump every 3 hrs i normally get 2-3oz per breast.if i pump after 5hrs,i would get close to 5 oz per breast. the other night,i gave my baby a bottle and waited 3 hrs from the last time i breast fed him.one breast was almost 4 oz but the other i struggled to get 2 oz.i normally didnt have to...when i feed from the breast,i hear my baby taking big gulps. i know pumping doesnt measure truly. but do i need to worry? or am i on the verge of having one breast to dry up? and if so,how long does it take for my milk to come back fully? ive been feeding from it more often.