Loestrin 24 Fe and better solution

This is my 3rd going 4th mo on Loestrin24Fe. The 1st month- it was great!! No PMS symptoms, got my period when I was suppose to and ended when it was suppose to. Onto the 2nd month, after being on it for a little over a week, I started to get PMS and all the other telltale signs that I was getting my period. And I did, it then lasted the entire month, ranging from very light to very heavy. At the end of the 2nd packet onto the 3rd the same thing happened only this time my "period" only lasted about 2 days and was very light. On Friday, I was suppose to start my "real" period and its Sunday morning and nothing. I had all the symptoms of getting it but nothing. I also feel like I am getting it. I am off to the drugstore to buy a pregnancy test, just to make sure!!! I took the pill on time everyday except for Thursday - the day before my period was to start. Has this happened to anyone else???