It helps me while I'm meditating. But, so far, it hasn't really prevented me from over-thinking the rest of the time.
I need to get rid of the distinction in my mind between "meditating" and "not meditating". Really, meditating - or mindfulness- is a way of life. I haven't got there yet!! But I need to keep thinking (haha!!) along those lines, and incorporate more mindfulness/meditation into my everyday life, even when I'm not "officially" meditating. So, for example, if I notice myself over-thinking, I could just be mindful of that and gently bring myself back to my breath. That's what I need to work at!!
PS: No, I haven't looked into the mat yet. Thank you for reminding me!!!!! I'll do that today for sure!!