Negative tests but having symptoms


So I have taken a few of the Mom med pregnancy tests and they all look negative to me, but just since last week I've had some pregnancy symptoms. My boobs are sore and feel heavy, I'm moody and more tired than usual. Maybe I'm about to start my period, but then again I never have these types of symptoms before my period either. Im due to start around the 28th of this month. So could I be testing too soon?