You are probably not pregnant. Pregnancy tests are 99.9% accurate these days, the fact that you're anxious and worrying can cause your period to be late. If you are only a few weeks pregnant, then I'm not sure you would be experiencing morning sickness so soon, but then I could be wrong.
You say you feel strange "down there". I'm not sure what you mean, but if you had unprotected sex with someone you only recently met, then perhaps pregnancy is not the only thing you should be concerned about.