8 weeks pp, IUD displaced/fell out - fertile or change of pregnancy?

My IUD was placed immediately after birth, I was sexually active again just before 4 weeks pp. My OB has been fairly frustrating throughout my pregnancy and pp and as this was my first baby and first IUD, I didn’t know what to expect with any of it. Anyways I had a 2 week pp visit and was told to wait to workout til 6 weeks, wait until 4-6 weeks for sex as I felt ready. They didn’t physically check my IUD and said that would be my next appointment.

After I started having sex again I felt some discomfort but assumed it was bc I just had a baby and it was my body getting used to everything again - I always heard you just have to get back in the saddle, it doesn’t feel great at first, etc. Anyways my OB wasn’t concerned so whatever, until I felt the string one night and pulled it out.

My OB then said it could have been not correctly in place this entire time and so likely wasn’t effective, so for all I know I’ve been having unprotected sex for the past 4 weeks. As much as I love my baby and eventually want to have more, the whole point of getting an IUD was so that it could be when I was ready in a few years down the road.

I don’t like how my OB has handled things at all so I’m changing providers, but what’s the actual likeliness of pregnancy and being fertile right now? I’m breastfeeding, and haven’t been having a ton of sex - maybe once or twice a week, but he’s finished in me almost every time I think. I haven’t had a period yet, but I stopped spotting around 6 weeks.