No period for 7 weeks, HPT negative just come off the pill...

Hi, I came off the pill in April because hubby and I are TTC. I had a regular cycle in May and June! I was so happy because I was worried about how long it would take untill my body got regular again! Anyways 2 weeks after my June period I got another period which only last 3 days and was very light! Since then I have not had my period! So my last period was on the 30 June!! So I haven't had a period for almost 7 weeks! I have done 3 HPT and all came back negative! The last time I tested was almost a week ago. I dont have any pregnancy symptoms, I just feel tired and have constant headaches and very hungry, I can feel my period coming but never comes! I was on the pill since I was 16 (I am now 27) so don't know if my hormones have decided to go out of whack! I went to the Dr last week and he said if the HPT were all negative then I am probably not pregnant but if my period still has arrived come back for A blood test... I am so confused I hope I am pregnant but don't want to get my hopes up! Has anyone else had this trouble coming off the pill? Was the cycle regular for first few months and then just went irregular? Thanks.