Took planb 9/15 after sex, had irreg. period (neg hpt). had unprotected sex again 10/21. next period due in 1wk. now spotting. planb effects or?

You need a plan: You need a better birth control plan. Taking Plan B back in september might cause some irregular bleeding for a day or two but after that it is out of your system. It would not affect your cycles in october. If you do not desire pregnancy then please schedule a visit to discuss better birth control options. Check a pregnancy test today.