horrendous breast feeding experience*please help*

I have a 17 month old son and a 4 week old son.

I am breast feeding my new born son and in the day, he feeds every 2 hours and sleeps nicely but in the nights he just wants my nipple in his mouth continously.

Doesn't sleep at all if I withdraw my nipple, it's very tiring for me to feed him all night and can't have proper sleep in the nights.

He doesn't even take Binky, I seriously don't know what to do and its leading me into postpartum depression, I have a toddler to look after during day time.

I want to exclusively breast feed atleast for 6 months and don't want to give top feed, I am doubtful If my supply is good but he is pooping, good amount of soiled diapers and putting on weight.