OK QUILTERS: Soooo yes indeed it IS the cutting mat!! I soaked it for a couple of hours with vinegar and a drop or two of dish soap. While I think it helped a little bit I can definitely see the mat has some deep cuts in it. So I turned it around and found an area that actually looked quite good. I did a bit of squaring of a tablerunner last night and my rotary cutter actually glided right along leaving nothing uncut! So... thank you allso much for your ingenious thoughts, you were all, 'spot on'!!
Next time I find a 50% off coupon for Joann's I will snap up a new mat.. and just to be sure a new package of blades! Trust me,..I will not be waiting another 12-15 years to replace a mat next time!!
Thank you again everyone!!