Am I pregnant??

Please post for me. I am 7 days late on my period. Last Tuesday I finally got my first positive pregnancy test after taking a million of them everyday for a week straight. So the line was super faint. (We are trying for baby #2) .. so I tested again about 1 hour later and again, a faint second line but it was certainly there. The next morning I took 1 more and same thing. On that Thursday I went to the health department to get the pregnancy confirmed but their test came back negative. They said it may just be because I'm very early in the pregnancy. I got curious tonight and decided to buy some cheap tests from CVS, they are just the CVS off brand tests. The test came back negative ( note that this test had the blue dye. The tests I took before that were positive were the pink dye.. they were the first response tests) ... so I guess my question is, am I pregnant? I'm so confused with getting positives and then negatives. I have felt fine other than alot of headaches and feeling a little nauseous. I have always heard the blue dye tests suck. So I'm thinking about going and buying the first response tests again tomorrow to make sure my positives are still showing up on those.... here is a picture I got on Tuesday last week...