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If you had been during your fertile days at the time of your sexual contact and if semen or pre-cum has come in contact with vagina, chances of pregnancy cannot be ruled out completely. The symptoms of increased tiredness, frequent urination etc could suggest chances of pregnancy. Wait and watch for your next periods. If you do not get your periods within 10 days of expected period dates, or if you develop any new symptoms, or if you suspect chances of pregnancy, you should consider visiting your doctor/gynecologist for thorough examination (to confirm pregnancy related changes/signs in body) and blood/serum HCG level test (to confirm/rule out pregnancy accurately). Be in regular monitoring and follow-up with your treating doctor/gynecologist and report any unusual/new/abnormal symptoms immediately. Drink plenty of water. Take adequate rest.
If pregnancy gets ruled out, and if you intend to remain sexually active (and if you are not ready for pregnancy), consider visiting your gynecologist to get started on suitable regular birth control measures to be protected (after your periods). Be regular with birth control use as instructed. Avoid having unprotected sexual contact.
Take care.