Can't get good Wifi signal anymore

[NobleTwoSix]

I got back after a 2 weeks Christmas break and now my computer can't get even a decent Wifi signal with my antenna. Before the break I used to be able to get at minimum 20Mb/ps and now I can only get at max 4Mb/ps. My parents are paying for 30 so wtf? I have a Rosewell RNX-N180UBE antenna. I also got a new desk for Christams and had to relocate my PC but when I put my antenna back to where it was I still can't get more than 4Mb/ps. Any suggestions?

 

[Mattios]

Can you run a speedtest on a wired PC? Could be that your internet speeds have dropped.

If you still get high speeds there then it's probably down to interference from a recent installation of a machine (microwave etc.)