Taking plan b too many times?

Hi, my boyfriend and I had unprotected sex today, he pulled out right before he finished, but the app says my risk of getting pregnant today is 27% so I'm still a little worried that there are chances of getting pregnant. Should I be worried?
Also, I took plan b twice in the past 4 months, I heard someone said that plan b hurts your body and if you take it too many times, you may not be able to get pregnant when you want to. I still want to get pregnant in the future but I can't get pregnant now. So continue the question above, if I really should be worried, will taking plan b for the third time really hurt my body that seriously and I won't be able to have kids in the future?
Thanks!