I don't think your pregnant. If it was vaginal bleeding, it wouldn't last that long. I'm pretty sure it was your period.
Was your flow normal? While a period isn't possible while pregnant, vaginal bleeding can happen.
I dont think you need to worry about being pregnant because you did get your period but then agian there are times when a woman can be pregnant and still get a period, but i really dont think you have to worry beiing you got it right away!!