Plan B

Last night my boyfriend and I had protected sex, but before he put the condom on he stuck it in me just to see how it felt. I was scared he got precum in me so I took a Plan B. Should i be worried? <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a> says I should start in 10 days. Will my period still be the same or will this affect it?