We're new cat owners who recently adopted an older boy of about 8 years old. He's not been eating or drinking since we brought him home over 24 hours ago. 

We set up his safe spot in the bathroom, and he's just been holed up in the sink. I don't think he's slept too. He's still so scared, think he also vomited a bit. He keeps shivering when we're around. Tried talking to him, leaving out his favourite food and snacks. Nothing. 

His previous owner mentioned he might have some time adapting, as they've had him all this while. So I'm not sure if this is normal cat behavior?

What can we do to help him feel more relaxed? To make him drink something at least. I'm so worried. Thanks in advance.