I hear you. I'm not super techie either, but I do try to pass on what little wisdom I can glean from the smart folks around here.
If you look under Options>Graphics one of the top settings above the Ultra Mode stuff one of them is called FSAA. The F and S stand for big words I can't spell from memory, but the last two stand for anti-aliasing. It's what makes the edges of your characters looks smooth instead of jagged around the edges. If it's set too high it's the biggest cause of lag in my experience.
But, if you haven't adjusted any settings it wouldn't have just changed on its own. So that probably isn't even it. If you know your system specs or even just what kind/model of laptop it is, it might help pinpoint the issue.
Also, which version of the client are you using? (Homecoming, Homecoming 64-bit, or Homecoming Safe Mode.)