Failed

when I was 6 weeks post partum, I got the copper IUD because I mentioned how I don't do well with hormones to my doctor. she suggested the copper IUD to me and I went with it. Well it ended up failing and my body rejected it. I went in (they could only squeeze me in to the walk in clinic so it was a different doctor) and so we went with the mirena(sp?). Well it's been 2 months and my first period after was super weird. Like one day of bleeding and a half of a day of spotting and then two days of nothing and so on. Then my last period was only one day. It's been about a week since the one day period and I went to feel for my birth contor today and my uterus felt swollen and hard like it did when I was pregnant. I only felt my uterus before when I was about 7 month pregnant and it feels the same exact eclxcept about half the size. I know the obvious would be to take a pregnancy test, but has anyone gotten pregnant from the same situation? Or anything similar? Or any advice for my situation? I've stressed so many times about being pregnant and ended up not being so I don't want to test for nothing. Or maybe I'm just putting it off. Any advice or encouraging words would be greatly appreciated. Please help.