jealous of moms that can comfortably breastfeed in public

My little one nurses fantastic at home or I can keep track of his schedule better and know when he is overtired or catch him before he becomes overtired. He really quickly goes from being okay to overtired tho... Whenever we are in public, it's so nerve wracking because there is a small window where I have before he becomes fussy and super hungry. It's also hard because we are usually super busy if we are out. I've tried to nurse him several times in public and he screams then I latch him on and he pulls off immediately and keeps screaming and fussing. I'm also debating whether he hates to be covered? I just drape a very thin scarf over him, made sure it's breathable. I would love to not have to pump and make sure we have enough with us or not have to go to the car to nurse him. I've def gotten less anxious about it but still frustrating. I guess I really have to make sure to catch him before getting overtired! :-/