Urgent Help please!

So I started up Steam to notice there was an update for Garry’s mod, I started the 51.3mb, no trouble. Then about halfway through the download stops completely to 0 bytes/s. Later it than starts to its 1.3mb/s as usual until it gets to its finishing point. Once it reaches the end like were it says 51.3/51.3 it just stays there. Now my steam game download go at 20kb/s and now I can’t play Gmod on this PC.

(User was banned for this post ("Undescriptive thread title, we're not steam support" - postal))

This is a bug with Steam, not the game.