Had sex on ovulation day, took Plan B 42 hrs later and 10 days after sex spotted 3 days, had period 2 days and spotted 3 more days could I be pregnan?

Low probability. Plan b is supposed to work within 5 days of use--120hours. Its hard to say whether or not you are pregnant because it's too soon but the fact that you bled for 5 days means that it is less likely. To be certain you would need to either take a home pregnancy test in 5-6 weeks, wait for your next period, or go to your doctor for a blood test.