It can but I have had the same thing happen with me. Your ovulation could be screwy or it could be that you caught your Lh surge at the end of your cycle (which happens) I would definitely wait until af is due and then test for pregnancy with an hpt... Good luck!
If the opk is positive, meaning the control line is as dark or darker than the test line than it can mean u are pregnant, check out this site..
http://www.peeonastick.com/opkhpt.html
I didn't know you could use OPK's to test for pregnancy. How does that work? If the line is really dark after you know you've ovulated?
Yes you can use them but I got three + OPK and one +HPT but I was not pregnant! A hpt should be + by now if you are. On this note though my RE does not trust HPT or the blood qualitive test! He only trusts blood quantative tests and says to never test until day 32-33 or 3-4 days past when you are late. So If you are late or when and you think you are go for the blood to see! I know woman who had the qualitive blood and was pregnant but it said BFN!!! I would say save your money and only use the OPK for OPK's and if your temp stays up for 18 days past O then you ar pregnant! Best of luck.
I've never heard of being able to use an OPK as a HPT. The 2 tests test different hormones at different times of the month. An HPT tests HCG levels (which is the hormone that's caused by being pg), whereas OPK's test Luteinizing Hormones which are given off before you ovulate. Is there a chance you ovulated late?