Taken from: http://www.early-pregnancy-tests.com

A false positive is a rather rare occurrence indeed. The two most common causes of, or explanations for, a false positive are 1) Use of hCG-containing fertility drugs (clomid is not one of them) and 2) improper use of test or failure to observe guidelines on test interpretation. With regard to the latter explanation, a false positive associated with improper use is typically caused by an attempt to interpret a test result after the given "reaction time" of a test. With most tests, you should not read a result after the five or ten minute time interval specified by the manufacturer. Hardly anything (besides fertility drugs) can interfere with a preg test result, so a true false positive is not a common occurrence.

If I were you, I'd make an appointment to see your doctor to get things confirmed - since you've not had a period in so long, you might be further along than you think.

Good luck!

False Positives happen I had one about 2 months ago. I was using the Clearblue easy digital test. So I don't trust those anymore. My sister has pcos and she said she tested positive a few times but they where all false.

I have PCO but I still have my period every month.. if you didn't have period for 6 months, i think you better check with the doctor to find what is wrong..