While having my inventory full, holding nothing in hands, I cannot pickup a drink and consume it. I had to drop one slot first, add the drink to the inventory and than can consume it.

Game said when trying to do this that I was holding something else. But is the fireaxe on my back when not in hands blocking my ability to drink?

Furthermore I experience a lot of lag when eating or drinking on low population servers.

Also when being sick it might be helpful to know what you are suffering from. As I last time got sick the tetracycline antibiotics did not help a thing. So I should have used something else but how to know?

Zombies keep walking and are visible through doors and walls.