thanks for using health care magic
Sexual intercourse during menses does not result to pregnancy
unless what you observed wasn't menses. Sexual intercourse during menses predisposes to infections since blood is a rich culture medium for pathogens. The symptoms you have cited could be explained by a genital tract infections which could have been favored by the unprotected intercourse
It would be advisable you meet your a doctor for proper examination and for investigations inorder to be certain with what could be the problem.
Best regards and hope this helps you.