I’m at my wits end...😓

My one year old has stopped drinking bottles, and will only eat weetbix! Apart from that, he’s stopped eating everything that he loves since getting his molars. He’s not pooping as much, and his nappies are hardly wet. What do I do?! I can’t do this anymore. 😭

Edit: he has been on cows milk for months. It’s only recently that he’s stopped drinking it.