Lagging in anything but in game?!

Um...I have a problem where everytime I play Crossfire, at a certain time of day, I always lag in lobbies, storage, item store, and blackmarket. The only time I don't lag is when I am in a game, meaning I can run, shoot, etc. This is really annoying because I cannot join a game properly because of the lag. Nothing is wrong with the internet. No one is downloading. I use internet by a cable (should be fast I think), Nothing else is happening at the moment? Can someone please try and help me fix this problem?? Please and Thank you!