What Are The Early Signs And Symptoms Of Pregnancy?

I started my period a week early this month, which I never do I have been a week late every month for a couple months until now. On the last day of my period, Sunday or six days ago,I had unprotected sex and he ejaculated inside me. Yesterday I had light brown spotting not much and today I have had less but enough to notice. I dont spot in between periods ever so I'm kind of concerned that by some chance I ended up getting pregnant. Could I be?