Hi, I had my last period on July 13th, 2012, it was 3 days and very light. I have not had a period for August and I took at test today and it was negative, could I still be pregnant?

It's possible. False negatives are very common.

See your doctor for a more accurate blood test.

Very possible, did you take it first thing in the morning with the first urine of the day for the best results?

But if still negative check with your doctor