Otherwise, I'm really not sure. I was hoping to know the answer myself.
although cats do love attention and company they are very independent animals and are capable of being in one room while you are in another,
its far more likely that your cat ,as all cats do, loves the heated temperature of the room, my cat used to sit next to me in the bath, also the microwave, cooker, kettle and even a cup of tea just made
so i wouldn't worry about separation anxiety just yet until you have more evidence of that.
It could also just be that your cat likes to be where you are sometimes, or particularly, he likes to be near you when you're cleaning. Cats tends to groom together if they are in the same family pack.
Heck my cat likes to use the bathroom when i do (his litterbox is in the bathroom) explain that.