If it's been at least 2 days since your last test I would take another one. Use your first morning urine as that is the most undiluted and has the most HCG levels in it. If your next test comes out negative and you are more than a week late call your doctor and make an appt. They may want to do some blood work and check your blood HCG levels, hormones, or thyroid. Good luck.
You could still be pregnant you could have just ovulated late, so a positive could not show up for a few more days. You could call the doc and have your blood drawn that is the only way to know for sure. Good luck!