Can't use apt-get (404 errors on mirrors)

So, I tried to run a simple command: apt-get install git

And got some errors such as bellow:

Err http://mirrors.digitalocean.com/ubuntu/ utopic-updates/main git-man all 1:2.1.0-1ubuntu0.1
  404  Not Found [IP: 192.241.164.26 80]
...

Then when I try to run apt-get update I get a lot of errors like these:

Err http://mirrors.digitalocean.com utopic/main Sources
  404  Not Found [IP: 192.241.164.26 80]
W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/utopic-security/main/source/Sources  404  Not Found [IP: 91.189.91.13 80]
...

Anyone have any idea of what the heck is happening?

(My VM is Ubuntu 14.10 x64)