Don't know for sure if I am or not. Please help...

I don't know

As hard as this is to do, try not to worry because it can delay it more. A woman does not necessarily always have her cycle the very same time each month for various reasons. I don't have the answer as to whether you are pregnant or could be. I'd rather not suggest you buy a pregnancy test because it sounds as though you are worried that you could be pregnant and do not want to be? If you really have good reason to believe that there is or could be a strong possibility, you might want to consider "Plan B". You have to do this quickly though.

I don't know your age and am not sure if you could get it without a prescription. If you have a clinic near you, planned parenthood for example, call them asap. Don't be ashamed or afraid to reach out.

Best of luck to you!