I think you're keeping a pretty good head about this. How far along do you think you are? Within the first month or are you further than that?
A friend of mine got unexpectedly pregnant. She's raising her daughter herself but with her mother's help, I don't believe the father was too interested. She thinks of her daughter as the best mistake she ever made. Maybe you'll see things differently later.
Assuming you actually are pregnant, your parents will find out sooner or later. If it were me I'd be more upset at finding out later than sooner....but that's just me.
Oh, and both doctors and store-bought tests give incorrect results. The doctor told my mom she wasn't pregnant with me and my mom had taken no test.....she knew. Took the doc a couple of months to figure it out....then again, that was a few years ago.
Good luck with everything and just keep a level head with it all. I believe that things tend to work out in the end....
b