What Causes Spotty Periods And Breast Soreness While On Loestrin?

I have recently restarted a birth control pill called Loestrin 24. However I am experiencing side effects i did not have the last time i was regularly on the pill. My past two periods have been spotty. My breasts have gone up 2 sizes. I have head aches and back aches. I have specific cravings. And I am easily heated. I had none of these side effects the last time i was on this exact same pill. Could I be pregnant or have and eptopic pregnancy?