Sorry but your funds was already stolen and you can't retrieve it anymore. Can you remember the software and apps that you have downloaded to your PC?
Let's say that you have been aware of protecting your security all of the time but you probably missed some random apps that you have downloaded and didn't noticed it as you use them.
That's true and that's one of the risks of keeping all your funds in a single wallet. I think you have downloaded or have clicked phishing sites that might hacked your wallet. It's a lesson for you to learn. You should secure your wallets and be mindful of every click and download that you will be doing. It's just sad that you have lost the funds that you have worked for.