You are getting puberty menorrhagia
and PMS and its very common in young girls.Birth control pills will only help in controlling the bleeding .So if you have cramps and nausea
the i would suggest getting some medicines for symptomatic relief.Birth control pills have a lot of side effects and i personally think that you are too young at present to sustain those side effects.No,you dont require a pap smear
to start OC pills but i would suggest that you try some medicines like ibuprofen
,mefenemic acid etc for the pain first before starting oc pills.Please consult your doctor for these meds.