Could someone give insight as to why this is happening (a question about birth control)?

I am on my third pack of Loestrin24E (birth control). And I have noticed some spotting (breakthrough bleeding). I know that's normal. However, I have been spotting for 10 days. And I have noticed an increased flow after drinking or eating some form of caffeine. Even my midol (contains caffeine) has increased flow 30 minutes or so after taking it (this also goes for tea and soda and even chocolate). The more the caffeine, it seems, the heavier the flow seems to be. Is this some MAJOR coincidence? Or this there an effect of caffeine on my period? On my birth control? Does it being a diuretic effect either my period or my birth control? Could this be why my spotting is lasting so long?