Suggest Medication For Severe Stomach Cramps After Removing Tampon

i have had really bad stomach cramps and after removing a tampon as i thought i was on there was a solid flat clear stretchy thing.... i am 9 days late but started the pill and am on my break now , im confused as to what the discharge is ??? and why my stomach pains were so bad if i am not on properly at all memerely blotching