Stopped birth control in jan. got my regular period on feb.20, but have not had it since then.had sex mar.31 and condom broke+mild cramping.is pregnancy likely or is my body still adjusting after bc?

Only one way to know: You could be pregnant. As you implied in your question, your body does take some time to readjust after discontinuing bc pills. However, there always remains the possibility of becoming pregnant when sperm enters the reproductive tract. My suggestion would be to get a home pregnancy test done.

Can take time : It can take several months to regain regular periods after stopping birth control pills. However, you still could be pregnant. Best to check a pregnancy test. If you are not trying to get pregnant you should consider more reliable birth control than just condom alone.