So, apparently i got hacked (or backdoored) and now i've lost 0.5602 bitcoins from my wallet since 21:32 GMT +1, the 31st of March.
I have NO idea how this could have happend as that i have full AV,
The recipient's address is "1FmMasfuEE6wtpzdWiVnDynfJ5tyyVbhP3".

Can anyone give me some advice / help here?