Plan B is well known for messing up our cycle. That's really common. That you used a condom protected you the first round of sex with your boyfriend. Unless the condom broke or you somehow use it wrong, you should be good. And the 8th is really pretty early for it to be a high risk time for pregnancy (although you can get pregnant any time during your cycle). The next time is also not a risk because you have to have a penis in your vagina. So, the bleeding is probably just your body dealing with the excess hormones it has in it from the Plan B. You are likely to be irregular for 2 to 3 months now. Make sure to use really good birth control (condoms in your case) because you won't ovulate on a normal schedule now either. Good luck