Could I be pregnant?

I normally go at least 3-4 days on my period but this time I only bled really heavy for one day and spotted the day after and today (3 days since I started my period) I got sick at work like threw up sick and I normally don't do that on my period. I am not currently on birth control because I am trying to switch over to a different form. Me and my boyfriend have sex regularly (sometimes without protection... I know I know). I tried to take a test but it was kind of generic and I did it correctly because I read the directions but no lines showed up at all? Any suggestions?