Hi, and thanks for your medical question on eHealth forum!
Since you have a slightly longer cycle and you had intercourse on 20th day of the cycle when the condom broke, it is good you took the Plan B pill. This acts by stopping ovulation. So you do not become pregnant. This is more than 99% effective in controlling pregnancy.
You can expect the periods to get slightly delayed because of the hormonal effect. Other than that if your periods date extends beyond the longest cycle, take a pregnancy test and see. In all probability this will not be required. Hope this helps. Take care!