I'm late

I was supposed to get my period on September 29th or 30th but it's late. I've taken several pregnancy tests but they've all been negative. About a week before my period was due, I DID have some very light spotting and some mild cramps (which is nothing like my period which comes complete with very heavy flow and cramps so bad I cuddle up with a heating pad). Could I still be pregnant even tho all my tests have been negative?