Help w/ Breastfeeding

Ok so I just had my son (my first) a little over 3 months ago & I've been only breastfeeding. I've tried pumping but he won't take the bottle. But now he's getting to where he gets mad if I switch sides & doesn't want to feed when I know he's still hungry. Sometimes he'll even start out mad, idk 😔 I've even tried going back to the bottle but he won't take it. It's getting to the point where I'm scared he's not getting enough at each meal time. Does anybody have any idea why or what I can do