is there anything i can do about it or is it gone forever ?
Bitcon transactions can't be reversed, so no, there's nothing you can do to get it back.
Most likely your computer got compromised, that means you can't trust your computer again until you clean it.
Once your computer is clean again, you can choose a new Bitcoin wallet. This thread is a good place to start:
[General] Bitcoin Wallets - Which, what, why? Good luck!