 [ Symptoms ] will strenuous exercise cause bladder infection and elevated psa [ Disease ] hi yes stress and anxiety will stop periods and so will your hormones exercise or trying to loss weight but also at 14 it often happens when your periods just stop could be for 6 months then restart it just happens to young women as for sperm on towels if you do not trust your father try having your own towel and keep it in your room as for the toilet seat i do not ever recall a women getting pregnant that way most women get pregnant from full penetrating sex but next time just wipe the toilet seat hope this helps you good luck