5 weeks pp chance of getting pregnant?

So at 3.5 weeks pp when I was starting to heal I tried to have sex again, it was painful but it was whatever and we did use a condom. Then about a week go at 4 weeks pp we got caught up in the moment and had sex again no condom but he pulled out (not safe I know) but since I'm breastfeeding I didn't freak out too much and just said that can't happen again. Well last night it did happen again and he came IN ME. So I'm kind of freaking out. I can not get pregnant again. I have my 6 weeks pp appointment tomorrow and I planned on getting the copper IUD but I don't think I'll be able to because of the fact there's a chance I might be pregnant. So moms my question is since I am breastfeeding what're the chances of me getting pregnant? If I were pregnant from the sex over a week ago it wouldn't show up on a test yet so will I have to wait to get the IUD? And also, I would take the morning after pill but since it happened over a week ago as well as last night there's a chance it wouldn't do anything for me right? I'm just a ball of nerves right now, any advice would be helpful. I heard it's nearly impossible to get pregnant while breastfeeding but I also heard you're extremely fertile after giving birth so idk what to think. And yes I know I'm an idiot for letting it happen, don't need a reminder. Thanks.