Am I really pregnant?

I had the mirena, and it came out last month. My doctor said to consider the bleeding from the mirena coming out my first period since having it put in. That was 9/1/09. It's now 10/8/09 and no period. I took a test last week in the evening and the line was so faint I didn't trust it. I retested the next day and got negative. Still nothing this week so I took another last night and again a faint line, another this morning and the line was so faint I could hardly see it. I thought it would be darker with first morning urine.... My doctor can't get me in til next week, so I'm wondering until then, am I really pregnant or is something giving me a false positive?