Addons deleting themseleves?!?!

Hey everyone I am brand new to this so I hope I am doing everything right. Any who I just got Garry’s mod 13 and have been having problems keeping my addons through workshop, they will install fine while in game but the minute I exit, steam will say it is syncing Garry’s mod 13 and if I go back into the game they are all gone and will proceed to re download. Any suggestions on what to do about this? It’s just really annoying that I have to constantly waste my time re-getting them every time I want to play. Cheers!

We will have to wait until update 20.

They’re glitching off the game for me.
SOME parts of the addons load, but the rest glitches up and I can’t use some parts of it.