Little one is not drinking water at all and not eating much food as well?

He is 13 months now n still need 2 formula bottles in the night. also he likes more sugary food and he will be cranky if we are not giving him anything he wanted. He is so stubborn baby now. He is hyper active so always wanted to play but these days he is not taking much food n stop drinking the water and then ultimately constipation happens sometimes. I am so worried as I am full time working mom I can’t pay much attention to him all the time.