Could Headache And Tiredness Be The Side Effects Of Morning After Pill?

I had unprotected sex (14th) for the first time, I didn t realise it was close to my ovulation period (expected period 28th). I took the morning after pill within 36h. Its has been about ten hours since i took it and still feel unwell, light headache and tired. I don t know if that is still the side effects of the pill or early pregnancy symptoms. Also where is a good time to do a pregnancy test?