Late period jump start

So I'm late on my period, today is day 8, I have been sexual active and there is a chance, but I also just moved from Wyoming to Louisiana and my diet has totally, so more alcohol and less healthy foods. What do you guys think it is? I just need a little advice and comments. I do not wanna be pregnant. I don't have any of the symptoms of pregnancy besides a sore lower abdomen. But no bloating, nausea, food averaions, mood swing. I'm all in line and very happy.