hi Anon - We have no way to tell if you are pregnant.
If you continue to worry about whether you are pregnant you can take a pregnancy test as there is no way we can tell whether or not you're pregnant. There are many reasons for a delayed period or a change in cycles that is not connected to pregnancy. Some of these may be a factor in your life, others may not but I will give you a run down of many reasons.
When you are under stress, your brain may go into alert mode, which can change your hormone levels, as well as affecting when you ovulate.
Ovulation is the time when your ovaries release a mature egg that is ready to be fertilized. If the egg is not fertilized, and does not implant in the wall of your uterus, your hormone levels change, and your uterus cleans itself out to get ready for a new cycle for the next month. That cleansing process is your period.
If you are stressed, you may ovulate later than normal, or not at all one month, which can delay or cancel your period for that month.
Hope all works out well for you,