Frustrated....getting discouraged...

When we were trying for our first child it took only one month! I'm on month four and I can't get a positive ovulation test...I don't understand what is going in. My cycles are fairly normal with the exception of two months ago it was 38 days long. If I don't get a positive ovulation test this month I am going to the Drs!!! I am just feeling very frustrated and starting to feel discouraged...I don't know what's wrong with me....