Ethernet speed problems

Since yesterday I noticed that my Ethernet connection is incredibly slow but I can't find any sign of it during ping tests, done through the cmd "ping -t x.x.x.x". I tried 8.8.8.8, from which I got a normal response time (40ms) and to my router which gave me 3ms contrary to the <1ms that I usually get from that test. I can't access any site, and from what I've seen from Steam (somehow that still works) the download speed is now around 1kb/s contrary to the normal 1.5mb/s. I don't think it's the cable because the issue is present for any terminal in the house. On the other hand the wi-fi is working perfectly. Thank you for your help