I have my laptop plugged into the AC adapter but it is showing battery mode and the battery is not being drained. When I remove the adapter it shows AC mode but the battery is being drained. I have tried removing the battery and AC, shutting down, holding down the power button and restarting but it hasn't helped. This is really bothering me because the laptop is running slower thinking it's on battery. What could be causing this and how would I go about fixing it?

I shut my laptop off last night and everything was fine but when I started it the next morning it was having the problem.