1 Bar on COD: Black Ops?

So, up until 3 days ago my connection on my ps3 has been perfect, I could load youtube videos and play online with no lag at all and now all of a sudden I can't join a game without getting any lag. I've turned off all of my computers and I'm still getting lag. We haven't moved the router or anything and it's around 5 seconds walk from me with no thick wall or anything. I went onto MW2 and I'm still getting a 1bar in every game and private game I join. Anyone know how I can fix it? I've tried unplugging my router.