Do I take a Plan B?

Karen
Basically I hooked up with some dude on Saturday night/ early Sunday morning and I'm just worried bc the condom wasn't put on properly.
It was less than 3 minutes that he was inside me, and I don't think he even finished/came.
It's been about 35 hrs since we had "sex"
I'm worried to be taking Plan B bc I took Ella last month, and I don't want to ruin my body hormones or wtvs bc I already missed my period because of Ella. I'm pretty sure I'm not pregnant bc I took a pregnancy test last week and it was negative, but my period just hasn't come yet and it's been like 6 days or more since it was supposed to.
I made stupid mistakes, and I know better to be having unprotected sex. I am planning on using birth control methods and making sure to use a condom every time.