Could I have been pregnant?

I had my iud removed 2 weeks ago cause it had shifted and my strings were messed up. Before the removal I had nausea, lightheaded, and slipped a period. I had talked to my dr and gotten an appointment and we chalked it up to the iud being messed up. I started bleeding today and I had a huge clot in the toilet. About half the size of my palm. My question is does anyone think I could have been pregnant or is it simply because of my iud being messed up and missed a period? Before the removal I literally had the same symptoms with my two successful pregnancies. I'm lost right now waiting on my drs office to call back if anyone's wondering.