Hi. first of all, read the newbie link please.
It is most likely that your ovulated early, and therefore your period came a week early too. If you don't chart, there is no way of knowing. Even if your period is typically predictable, it is possible to have a strange cycle. I don't think you are pregnant.
If you are pregnant enough to have symptoms, you would be pregnant enough to get a positive pregnancy test. Take a test if you are unsure.