I had sex on the Nov 11th and took a My Way plan b on Nov 13. I also to a pregnancy test on the 14 and it came out to be negative but lately ive been have lower back pain along with mild abdominal cramping. Ive also been loosing my breath alot easier and ive been having a constant headache everyday AND very frequent heart burn and its becoming alot harder to keep my food down like everything has been sitting on my chest along with not being able to sleep comfortable unless im on my back or my side.