Ovulation & condoms


Just wondering if any body could help me out. I’m not currently on birth control and with my <a href="https://play.google.com/store/apps/details?id=com.glow.android">ovulation calendar</a> it says I have a 33% chance of becoming pregnant, I had sex but he wore a condom, do I still have that high of a chance should I buy plan b?!