Thanks for writing in.
If you have been using these birth control pills properly, it is extremely unlikely that you are pregnant. They are one of the best contraceptives available. Oral contraceptives are known to cause spotting and cramping. But since you have been experiencing these only for the past 2 months, I would like to rule out some other problem. I think you should see your physician and get an ultrasound
of the pelvis done to rule out another problem like adenomyosis
Hope this helps.