Hi and welcome

I expect he is a little disorientated after the move - your new apartment will smell strange to him and he is probably missing the other cat a little. However keep playing and interacting with him and he should settle down in a few days. Looking forward to seeing photos of your cat.

I will post some pics when he wants some attention, that way I can get a somewhat decent picture with my webcam(it attached to my laptop)

A companion would be good for your kitty, and you will find loads of little uns in the rescues this time of year. However if you really dont have the space for another, keep loads of toys and activities about so kitty wont get bored