You aren't, it's not possible to menstruate every week. If you're experiencing vaginal bleeding on a weekly basis then there is something wrong, you need to go see your doctor.
why my period is come every week and 3to 4 days.
you could be pregnant.
Normal !
Having your period means you did not conceive!
If you are still having a period, you are not pregnant.
Your period occurs once a month.
by taking medication like painkillers
Usually you get PMS symptoms about a week before your period is due to start.
NO.
Yes. You can get pregnant at any day during your cycle, including when you are on your period.
You're pregnant
If you took them every day for a week you would delay your period by one week.