Pregnant with IUD

I found out im pregnant and I have an IUD that is still In place. Went to the ER yesterday my hcg levels are 403 had a transvaginal ultrasound and iud is in its place but no sac found anywhere. I’ve been having spotting on and off for the past week sometimes lighter sometimes a little more with like mucus. (Sorry TMI) does this sound more like a ectopic pregnancy??