Day 12 of my cycle condom broke and he came inside. i took plan b 30 mins after. can i still be pregnant?

Unlikely : Plan B One-Step is up to 89 % effective when taken within 72 hours (3 days) after unprotected sex. It can reduce chance of pregnancy by up to 95% if used within 24 hours. It continues to reduce the risk of pregnancy up to 120 hours (5 days) after unprotected sex, but is less effective as time passes.

Unlikely, but yes: Plan B is good but not 100%. Recheck a pregnancy test in about 2 weeks, as the package instructions say. Consider more reliable forms of birth control in future.