If your period is not regular you might be under stress and for some reason the period is late. At this point I am guessing everything is clear now, so what was the issue?
I think u shld consult gynecologist. You might be pregnant. Good luck!!
Since your period isn't really regular, you would need to wait a few more weeks and see if it will come. Usually, pregnancy tests are reliable and if you are really pregnant, as early as four days after conception, they can detect it. So it's more likely at this point that you're not pregnant, since you're already a month late. However, I would still check and wait for another month. If you want to be extra sure, you can consult an OB-GYN which can accurately know if you really are pregnant.
So yeah, wait a week or two more and test again. If it turns out negative, then it's most likely that you're just delayed and not pregnant. Good luck and take care!