I've Had Brown Spotting On The 2nd Of This Month

I've had brown spotting on the 2nd of this month but not followed by a cycle. I've taken a pt on the 7th of this month (negative). Another pt on the 11th (positive) which brand was first response. Another today, 1-16-16 negative, different brand. I had sexual Intercourse on December 26, could it be to early for testing or am I not actually pregnant?