Well how long is your cycle usually, and how many days is it into your current cycle?
Yeah, I would definitely test or see a doctor. If you know that you are late, that should be a big red flag going up. I wish you luck! Also, I have this app and it is GREAT, it keeps me organized I am able to enter all kinds of information... How I'm feeling, if I had protected or unprotected intercouse, positive or negative pregnancy tests and it's like a calendar so you can keep your menstrual cycle organized. I highly recommend it. It is called Menstrual Calendar, it is a pink icon that looks like a calendar. And is free!
My cycles seem to be at least 30 days. and I think I am about a little over 20 days into it.