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If you were during your menstrual bleeding time at time of sexual contact, chances of pregnancy are less/nil as chances of egg being present in your system at that time is nil. There are no studies to prove that sperms can swim through fabrics (unless it is thin and lightly woven and there is ample vaginal wetness). Wait and watch for your next periods. Look out for development of any new symptoms. The abdominal discomfort could be due to the ovulation pain or could also be a result of physical training. Consider taking rest for a few days. Visit your doctor/gynecologist for further evaluation and assistance. If you intend to remain sexually active, 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.