My 6yo has been occasionally down on himself for a few months now - I spoke with friends and a few said theirs were the same and it was normal and not to worry. DH also spoke with a child psychologist friend who said it was not unusual, and to carry on praising the processes rather than results. But he seems to be getting harder and harder on himself, gets frustrated when he doesn't achieve what he wants/doesn't win (we put no pressure on him at all and focus on participating not winning at the various sports he does, and neither DH or I are competitive), tells us that he is rubbish and that no one likes him. He's actually the opposite - very capable, very likeable and popular. He also says he looks rubbish. :(
More concerning now, in the last week, he has started to hit himself on his arm, hard enough that he leaves a mark (does soon fade).
Is this within the realms of normal?
The only thing I can think of which may have triggered this is starting a new sport where all the others were a few years older than him, and he is obviously not as capable as them yet. He's stopped that class now at his request, but is still saying how rubbish he is.
Advice welcome please.