After lunch, I felt at a loose end and roamed about the little flat. It suited us well enough when mother was with me, but now I was by myself it was too large and I’d moved the dining room table into my bedroom. That was now the only room I used ; it had all the furniture I needed; a brass bedstead, a dressing table, some cane chairs whose seats had more or less caved in, a wardrobe with a tarnished mirror. The rest of the flat was never used, so I didn’t trouble to look after it.
After lunch I felt at a loose end" means
The flat did not really suit him any more because
He did not look after the rest of the flat because
“... Now I was by myself it was too large". The word it here refers to