Constantly getting disconnected from Steam Cloud/Community can't be enabled ingame

[Doomish]

I don't know what the problem is. I've checked my firewall and the router, but every single time I go into any Steam game, I either can't get Community to come up (problematic in TF2 because it disconnects me), or I lose connection to Steam for seemingly no reason. I've restarted endless times and it never helps. Can anyone help me diagnose the problem?