It is possible that you got pregnant then. Even during ovulation, however, not every single sexual encounter is going to result in pregnancy. If you are wondering if you are pregnant or not from that, you would have to take a test.
As Critizin said, the pull out method is not reliable. If you are trying to avoid pregnancy, you should be using an actual method of birth control. Having an irregular period does often make it more difficult for a woman to get pregnant, but that certainly does not mean that it is impossible or that she does not actually need to use birth control.
You are right that there is often a stringy discharge during ovulation. Since your cycle is abnormal, it will be a lot more difficult for you to track when you are ovulating. That is why so many women with irregular periods have trouble getting pregnant. There are other ways to track ovulation as well.
You should talk to your ob-gyn about possible problems that could be causing you to be that abnormal, if you have not done so already. If you are trying to get pregnant, you could also ask her about other ways to track your fertility. If you trying to not get pregnant, then you could ask her about birth control.
