Un latching and re latching

My 7 month old boy won’t stay latched. Over the months it has gotten worse. Now every few seconds he in latches and looks away for a second then starts eating. Sometimes he will stare at me for a minute. For one this hurts like a B**** when he lets go and latches again. He starts screaming and crying if I try and re direct him to eat again. He also won’t relax while he eats he just pulls my nipple out as far as he can. It’s to the point I like literally can’t feed him anymore I’m in so much pain. Would a lactation counselor help with this at all or will they say he’s to old to fix anything? What should I do?