Well not taking your pills correctly does increase your chance of failure. So it is possible that you could become pregnant. The things that you are describing are all hormonal reactions. It could be from pms, pregnancy, or the pill itself. If the side effects you are experiencing are bothersome you may want to speak with your doctor about swithing brands or methods altogether. After being on the pill it gradually will cause your period to be lighter and shorter. So you should not be concerned with this. However, If you are concerned about being pregnant the only way to tell is to take an at home pregnancy test or to go to the doctor for a blood test. Your birth control will not effect the results.

Birth control pills are not 100% effective. So even if you did take them every day and at the same time every day, you could still get pregnant. However, like mc4 said, you have not been taking your pills like you are supposed to, so that increases your chances of getting pregnant.

Pregnancy is not the only thing that can cause those symptoms though. There are many things that could cause those symptoms. I would suggest taking a pregnancy test. If it is negative, tell your ob-gyn about your symptoms.