My doctor says I'm due march 2,2011 but when I calculate my first week is on may 26, 2010 so when did I get pregnant? When is the day I actually got pregnant?

I would say end of June maybe

Rough guide would be to count ahead three months and add a week. If you know the first day of your last period, you would go the opposite direction... counting back three months and adding a week. This is only a rough guide, however as you would have most likely ovulated somewhere in the two-three weeks after your period.

Unless you had certain types of medical assistance to conceive, you won't know the exact day of conception.

You can come down to a several week time frame, but the exact date ( specific day) can't be figured,

According to my gestational wheel, the same one your doctor used, you most likely conceived on or around June 6. Now, please understand that this is not exact and can go approximately 2 weeks either way.

If you are curious about paternity you will still have to have a paternity test done.