Gigabyte Aorus Gaming K7

Hey folks, I'm running out of ideas here.. Gigabyte Gaming K7 X370, 2 x 8GB Ripjaws, RX 580, EVGA 850W Modular PSU, Red Devil RX580 8GB, 2 4TB HDD, 2 240GB SSD. First of all, system is running flawlessly since December, 2017. No hardware change since. Few weeks ago I wanted to boot...

So basically one day out of nowhere, my connection, which used to be 75 mbps dropped down to about 5. Since then it has just gotten worse and on some days it doesnt work at all, while on my phone there are absolutely no issues (wireless). It is a PC so I don't have an option to use WiFi on here...