All of a Sudden I get Major Lag

3 days ago, my ping and fps are fine and I didn't lag too much. Just yesterday, I logged in, joined a game, and had a constant, huge lag. I check my ping and fps and they are fine but i'm just overall lagging like a serious btch now. It's getting me furious because I havn't been able to play for 2 days and I wana play bad. No virus scan is running, I've restarted the comp about 3 times, and no viruses in the computer. HELP!