Pregnant or something else?

Hello, I was wondering if I was pregnant or suffering from something else like stomach flu....This is my fifth day having abdominal cramps. The last two days I had continuous upper/middle abdominal cramps along with a lot of nausea, dizziness and one massive headaches. The first two days were occasional. I also thought my period shouldve started this week. I haven't seen any spotting and if I were pregnant I wouldve been finishing my third week on the 3rd day of this. I also have no breast changes or constipation or extra discharge or anything. Also I've been quite stressed out emotionally the last few weeks thinking about this. I don't know what it is. My boyfriend got inside of me. I touched very small amounts of his pre-cum and then just rubbed it in on my fingers so it wasn't visible. I don't remember exactly what happened but I remember touching myself to guide him. I never went inside but I was on the outside of my vaginal hole I think and think other places and was very wet. Could that cause pregnancy? Could all this prove pregnancy?