What Causes Delay In Conception?

I ve been having trouble getting in contact with my doctor due to my work schedule (I have no time during the day to be on the phone). So I thought I d try this! I got off BC about a year ago due to headaches. And i ve having semi regular periods since. My cycles were sometimes way long, and sometimes normal. My husband and I are not quite ready to start trying to conceive so we ve been using condoms. I went in to my doctor on August 18th for my annual pap. I had not yet had my period. I ended up not having a period at all in the month of august. It s now September 14th and still nothing. I took 5 home pregnancy tests at different times, all negative. I ve been taking an herbal supplement called dong quai to try and move things along, and so far that has done nothing as well. I ve been having some cramping, but thats it. I m just getting frustrated, and concerned and I m not sure what the next step needs to be. I m worried when my husband and I are ready to start trying to conceive, I won t be able to. I used to have irregular periods as a teenager and did skip months here and there, but dong quai usually did the trick. But I ve not had any issues since then. I would appreciate any help! Thank you!