MBP Trackpad in "click & drag" mode

Hey all,

Every once in a while my track pad gets kind of stuck like it's clicking and dragging. I'll be on a web page and move the mouse and it highlights all the text. On the desktop, it drags across and will select the icons on it. I'll click out of it and when I move the mouse it just happens again. Sometimes it will go on for 2-3 minutes and other times it goes on until I've had enough and just restart my computer because I'm tired of it. It's been doing this for a while but it does get irregular (once a day to every other day or whatever), but it happens enough to make me pretty mad.

Does anyone know what the problem is or anything to fix it?

Thanks.