This is caused from the morning after pill you took.
You ARE NOT pregnant. You took the morning after pill. Relax.
You need to wait until your period is due (the 23rd, right?) and take a pregnancy test. NOTHING can be done now regardless of if you were or were not pregnant.
When you do start your period, I suggest you high tail your non pregnant self down the your local family planning clinic and get some birth control so that this kind of deep down anxious fear does not ever happen again.