not feel (oneself)
To not feel physically or mentally well; to not feel as one normally should. I'm sorry for getting upset at you earlier. I just don't feel myself today. I know Mary hasn't felt herself ever since her cousin died.
not feeling oneself
and not feel like oneselfFig. to feel upset, troubled, or disturbed in some way. I'm sorry I said what I said. I'm not feeling myself today.