Hi Welcome to HEALTHCARE MAGIC..
I have gone through your query and can understand your concern...
Yes
pregnancy is possible through sexual intercourse during
menstruation, however chances are very less. It is uncommon for a woman to ovulate during menstruation.
The symptoms like hurting stomach,
fever, food carving & senstive nipples should be because of hormone chance related to excessive
stress & anxietry of getting pregnant. Because pregnancy should not cause symptoms such earlier.
Now she should wait for her next periods to come. If her periods are delayed, she should do a pregnancy test.
Refer to a doctor, if fever like symptoms persists as they may be relatedto some other problem as well
Hope your query is solved
Good luck