effect of taking plan b twice in one month?

Hi,
Welcome to ehealthforum,
The emergency contraceptive pills contain high doses of hormones which can upset your hormonal and period pattern causing delay in your periods. Wait and watch for your periods which can be delayed. Visit your doctor/gynecologist for further evaluation and assistance. If pregnancy gets ruled out, and if you are not ready for pregnancy, but 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 and avoid repeat use of emergency contraception.
Take care.