Don't know what's going on.

I am 25 years old, married and trying for a baby. I went to the gynecologist in march, and all was physically how it should be. The first day of my last menstruation was 1 May 2011, that's about 3 months ago. All the home pregnancy tests are negative. I'm going to take a last one tomorrow, and if it's still negative I guess I have to go to the doctor? Is this normal? Are there specific blood tests that I should request to check my hormone levels? I'm really confused right now..