What Causes Tightness And Stabbing Pain In Abdomen?

Around the 19 of March my boyfriend and I had sex, the condom broke, I was nervous about becoming pregnant so I took the day after pill about 32hours after. Then what I believe to be my period started on the 31 of march and ended on the 5 of April. On the sixth my stomach felt a little tight from my belly button to my right side. On the seventh is was hurting on and off so badly that is almost felt like someone was stabbing me. I went to Urgent Care and they told me it seems i may have pulled a muscle. However after doing some research I know that during early pregnancy it is common to have pain in that same area due to the stretching of the uterine wall, plus in the morning I have been feeling ill not to point of vomiting but just sick to my stomach. Do you think it is possible I am having pregnancy signs?