Does Delayed Menstruation And Spotting Indicate Pregnancy?

I HAVE A HISTORY OF PCOS, WITH IRREGULAR CYCLES. FOR THE PAST YEAR I HAVE HAD REGULAR 28 TO 30 DAY CYCLES. I WAS SUPPOSE TO HAVE ONE DEC. 31 IT IS NOW 3 WEEKS LATER, I TOOK A TEST 2 WKS AGO AND IT WAS NEGATIVE. NOW IM LIGHTLY SPOTTING NOT ENOUGH FOR A PAD. COULD I BE PREGNANT.