Ovulation tests

candee

So I have PCOS I took a Clearblue Advanced Ovuation Test on cycle day 13 it was positive I did another one on day 15 it was also positive, it is now day 20 and I am having some very mild cramping I did another ovulation test and it again says positive... how can I still have a positive ovulation test 7 days later? Has this happened to anyone else?