My 16 month old bit my boob!!!

I haven't nursed him since he was about 8 months old. I'm now 6 months pregnant and for the last month he has been OBSESSED with my boobs. He puts his hands in my shirt or he'll pull it up to try to get to them. He pats them or pinches them when I pick him up. He rubs them when I rock him before bedtime. And tonight when I was rocking him HE BIT ME. Right above the ninny!! I SCREAMED so loud it scared him, he started crying, and I was crying Bc it drew blood and it's like on fire still 😭 how do you mothers who nurse to a year or more do it?! Why is he all the sudden obsessed with my boobs??