“….is absence of suffering happiness ….. I don’t feel so.”
It is not, Mahi. Consider this case. A patient is in pain (suffering). Medics apply medicines and other treatment and the pain goes.(absence of suffering). After that, his wife or gf visits. (happiness).
Now if the pain returns (while the wife or gf, the source of happiness, is still there) at once the happiness is gone. So there can be no lasting happiness where suffering exists or comes to exist at some point. (the 31 realms) .
You say : ‘Happiness is an illusion for me..world doesn’t make me happy..yet I am not unhappy unless of course strong mental or physical vedana arise” So, since you ask what state it is, I say it is the neutral state. But as you have seen yourself “unless of course strong mental or physical vedana arise”; you of course mean strong BAD mental or physical vedana. Not’unless’, Mahi, they WILL surely come, if not sooner then later. So there can be no permanent ‘neutral state’ of neither-happiness-nor-unhappiness either.
So strive for Nibbana. That alone is true happiness.