OS X 10.10.3 Wi-Fi crash

Ever since I've updated my Mac OS Yosemite for the latest version 10.10.3, the issues I never had with my Wi-Fi, started ocurring. Now I can only seam to mantain a Wi-Fi connection for like 20/30min, after that the tool crashes (it wont show any network and the icon wont change from the status it had before the crash).

The only way to recover from said crash is to reboot the whole machine. But even so, sometimes, I have to restart the computer right after a restar because it didn't recover.

This being said, I've already tried to delete the Wi-Fi configurations and add it again in the Network window with no luck whatsoever. Added to this, the internet really seams to be unstable since it often travels from a good responsiveness and quick navigation to an extremelly slow connection. Although, oddly enough, when I test the internet connection using websites as speedtest, it says the internet speed is perfect.

I really don't know what else to do. Right now I'm accessing internet using my iPhone as a cable connected hot-spot.

Any help would be greatly apreciated.

Thanks in advance.