Can anyone tell me if it is possible that I may be pregnant?

I have always taken ortho-novum 7/7/7, but 7/3 was switched to generic (necon). On 7/10 I started to spot (which I have never done in 8 yrs of taking the orhto-novum), and am still spotting now (6 days later). I called the doctor and the pharmacist, and was told that the necon is supposed to be a direct replacement for the o/n, but that there must have some difference that my body was reacting to. They told me that even with this, there still should have been enough of the hormone to protect me from preg. However, I was ovulating anywhere from 7/11-7/16 (if the ovulation calander is right)and we did have sex (assuming that the b/c was working as it was supposed to), so I am just wondering if I could be preg? I can't get in to my doctor until 8/20, so I don't want to worry from now until then. Also, now I am 3-4 days from starting my period (it should be either Saturday or Sunday, it fluctuates) has anyone had great success with a particular brand of Early pt?  If so, which one and how soon can I test?  The waiting is driving me absolutely crazy!!! Any help would be appreciated. Thanks!

[arv]

This was a repost because I didn't get any answers earlier - sorry, I spotted until 7/16, then they switched me back to the Ortho Novum.  I just feel a little weird - I don't know if it is my body telling me that I am PG (because I would like to be) or if I am just looking for things that have always been there (that I didn't notice before).  Thanks for any and all help!

[Casey1]

The pill works by stopping ovulation (did you not know that?).  As long as you took the pills as prescribed, it is very unlikely that you ovulated and therefore that you became pregnant.