...to find out if you are pregnant or not you need to test.
we can't tell you if it will be positive or negative, you would have to test.
and by sounds of it, you have an irregular period maybe.
anytime you have unprotected sex, there is a chance of pregnancy.

If you are wondering if your regular cycle (in your case, sometimes missing a month)will affect the test results, the answer is NO. There is a little strip in every test that "reads" a hormone only present when you are pregnant. The HCg. Your normal missing monthly will not affect these results. Now if you are wondering whether your test will be positive or negative, we cannot tell you. If you are irregular on your periods, you need to figure out when you are most likely due for a period, and in your case, wait two days after that to test. The only reason I suggest that is because your periods are irregular. How old are you, just out of curiosity? Is your period a new thing, meaning did you just start having them? If not, I would suggest seeing a gyno just to rule out problems. It is not in the norm to miss periods.