BitDefender slows down my download speed that it is measured in kilobytes

Title said it all. My download speed is literally measured in kilobytes while BitDefender is active, as soon as I turn off the protection shield it comes right up.

I tried reinstalling BitDefender and even reinstalled Windows but nothing changed (also reinstalled/updated my wificard drivers, this problem happens with the internet cable plugged in aswell).

The thing is that if I disable Windows firewall entirely half of my download speed comes back. What should I do? P.S. I am using BitDefender free edition with a fully up to date Windows 10 copy