Have you tried verifying your game cache to make sure none of your files are corrupted? You can do so following these steps Verify Game Cache Files. Are you connected to the internet via wifi or wired? Also, please feel free to try the suggestions listed here:
I tried all of the Tweaks and Fixes things before already, but it didn't help. That's why I asked here.
I tried verifying my game cache, but it didn't change anything, there wasn't even anything wrong at all.
The good thing about it all is, that I didnt have any lags today. I played a few matches (even before verifying my game cache) and everything was running smooth and lag-free. So the lags just disappeared for no reason.
I hope it stays like this from now on.
Thanks for the tips though