Help.

Help any other mommys go through this? My son (who a month old) latches but with a nipple shield due to my nipples being flat :( but only for a few minutes then pushes away but won't relatch sometimes to the point where he all red from crying bloody murder! I try to calm him but he won't relatch sometimes so I have to give him the bottle off either Brest milk or breastmilk that I keep handy just in case I need. How do or I get him to calm down songstress way he can latch on.