So I've been trying for a baby for about 3 months. I came on my period October 2nd for a few days and now I am into November and it's the 10th and I haven't come on. But my natural due date for my period is the 13th. But last month, why did I come on so early and only for a few days and why haven't I come on my period on the 2nd this month? I've had cramping and sore breasts and two invalid pregnancy tests( not come up with positive or negative result) could I be pregnant?

Assuming that you have had unprotected sex, then yes you could be pregnant. However, if your due date is the 13th it is too early to take HPTs and too early for physical symptoms to manifest.

Were you on birth control medications prior to your starting to become pregnant? Stopping such medications could have an affect on your cycle. Also the tension of trying can have a negative affect on conception. Three months is a very short time to be trying. Relax and let it happen and enjoy the process.