Well i went to my doctors after a year of ttc and because i had not done my bbt he suggested i do this for 3 months and then return back to him. We did this and have had lots tests, DH has had a sperm count carried out, i have had numerous blood tests, a Hysterosalpingiogram (sp) (which did not go as planned) and a Laparoscopy which confirmed that i do not make the right hormones for my body to ovulate.
I would say that although it has not been long for you both to get in touch with your gp and maybe make an appointment to discuss matters further, dont be shocked if they say leave it a few more months at least you have got in touch with them and they know the situation.
Good luck to you both