If those are your symptoms I'd go see a doctor now. You certainly aren't pregnant and feeling symptoms already, that's just not possible. There might be something seriously wrong wit you if you're constantly shaky and nauseated. Talk to someone about it and have them take you to a doctor.
As for your questions. You didn't give us enough information to give you any real information. You will not be able to detect a pregnancy until you miss your period (well, that's not entirely true... it's possible 10 days past ovulation, it's just not likely).
Where are you in your cycle? When should you get your period?
Mention your concerns to planned parenthood when you go on the 21st. they'll take care of you.