I'm not sure what's going on

Hello,

I am a 27 yof who has already had two children. My recent husband and I have been trying to conceive now for over a year, but with no luck yet. For the last six months I have had my period on the twenty fourth of each month, no matter the length of the month it still comes on the 24th. I am now eight days late. I took a pregnancy test on the day I was due for my period to start and it was neg. I also took another one on the 27th at my dr office. I was there for a fertility work up. Here I am on day eight of my non exsitant period, and I don't really have any pregnancy symptoms, my question is can I be pregnant or if not what is going on?