Our cat is scared of being on his own

I don't know why. I came upstairs one morning and the cat, Asterix, was running around and jumping up on things. After that day he usually doesn't like to be alone in a room. He even follows us in to the kitchen at tea time. Although that might be because he hopes to get some leftovers.

This morning there was a storm. I went upstairs a few minutes after my sister had left for school, so that Asterix wouldn't have to be on his own. But when I came upstairs I couldn't find him! He usually always comes when someone walks in to a room. I went to the bathroom, and when I came back out after a couple of minutes Asterix was practically climbing up my legs. I still have no idea where he was hiding, but nothing is broken or clawed apart so at least that's good.