Possible Pregnancy?

During the last week of June, while on my last day of my period I made a drunk mistake and had unprotected sex. The next day, after work I went to rite aid and bought the morning after pill. The pill made me feel very sick but I did not vomit. 

Now here we are on the last week of July and I am 9 days late. When I was two days late I took 2 pregnancy tests. Today, at nine days late, I took another. When I took this one, it was negative. All tests have been negative and I'm freaking out because I have had stomach pains and nausea all month. On  Friday I had very sharp pains similar to period cramps on my left ovary. Still no period, right now I have smooth tacky discharge and my cervix is hard and high. I'm not looking to have a child so this is really frightening. Can the morning after pill cause you to skip an entire period?