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Your symptoms (sore nipples, bloating, frequent urination, headaches) could be suggestive of pregnancy. Look out for development of any other new symptom suggestive of pregnancy. Pregnancy can result if you have unprotected intercourse after your periods as you become closer to your fertile days. Visit your gynecologist/doctor soon to have examination and blood HCG test to confirm/rule out pregnancy. Maintain good diet, healthy lifestyle and drink plenty of water and juices to keep your hydration levels good. Take adequate rest and avoid any heavy work.
Take care.