S.M.
First I would call your Dr and have them test you, then if you are not pregnant I would recommend learning how to do your BBT (Basal Body Temp) and chart your cycles, it is easy to do and you will be able to determine when you ovulate and even when you are pregnant, I didn't need to use a hpt on my second child all I had to do was take my temperature... and I know I was pregnant. there is a book and a website called Taking charge of your fertility, by Toni W (I forget how to spell her last name) I think the website is tcoyf.com but you can google it if I'm wrong... I'm done having kids so I haven't needed to refer to it lately but it got me pregnant 3 times (4 actually but I had one miscarriage).
if you have any questions feel free to ask