The pill, even when taken on the first day of the period, cannot become effective in less than a bare miniumum of seven days (and more commonly, one full cycle of pills), so no, it is highly unlikely your birth control was effective by yesterday. If you do not wish to become pregnant, I suggest you get emergency contraception as soon as possible. You must do so within 72 hours.
If you DO wish to become pregnant, you need to stop taking the pill right now for the health of the possible fetus.
As far as your reaction, I have not heard of the itchies as a common reaction to hormonal meds, so I would suggest you call your doctor.
In the future, please get the full info on medications before you take them, especially birth control. There's no sense in using a given birth control method if you don't know enough about it to use it effectively.
Editor and Founder, Scarleteen
My epitaph should read: "She worked herself into this ground."
-- Kay Bailey Hutchinson
[This message has been edited by Miz Scarlet (edited 10-09-2002).]