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Sperms can stay alive for about 20 minutes even in dry condition. If pre-cum or semen was present on finger or has come in contact with vagina during genital contact, chances of pregnancy are possible (chances are high if she was during her fertile days at the time of sexual contact). The recent symptoms that she is having could suggest pregnancy possibility. Wait and watch for her periods. Look out for development of any new symptoms if pregnancy is suspected. She should visit her gynecologist for further evaluation and assistance if she does not get her periods within 10 days of expected period dates, or gets abnormal bleeding. If pregnancy gets ruled out and if you are not ready for pregnancy, but intend to remain sexually active, you should consider getting her started on suitable regular birth control measures to be protected (after her periods). She should be regular with birth control use as instructed. Avoid having unprotected sexual contact if you are not ready for pregnancy.
Take care.