Quick medical question?

I am is a few days late on my monthly. I have been getting cramps on and off like I am going to get it but then don’t. I was also nauseous a few days last week (though it went away after I ate and had water), and have been a little more tired then usual. Could something be wrong OTHER then me being pregnant? My boyfriend is freaking out because the video game versions of us in Tomodachi life (a 3DS game) just had a baby. I’ve tried looking things up online and haven’t found anything, and I’m not sexually active and haven’t been for months since he had to move back to NYC. I’m thinking I have a stomach bug and it’s just the giant load of stress placed on my lately that is stalling it. Any ideas? Google and medical sites aren’t helping much >.>