How to hand pressure in sports?

[JamesHaldane]

Hey there guys, I am in my early teens and am quite a capable cricketer. I destroy everyone with bat and ball but fail to replicate this in real game scenarios. I am an aggresive batsman by nature and I get rattled VERY easily. I Loose my cool and attempt to hit out.

So my question is how can I be relaxed at the crease and not put so much pressure on myself to perform.

thanks