Fluid in uterus - anyone experience this?

Has anyone ever been told they have fluid in their uterus? This was 5 days after I had any leftover period spotting at all and one of the reasons they cancelled my IUI, because it was discovered at time i was supposed to trigger. The nurse said I probably just wasn't done bleeding yet but I never bled at all after this (or in the 5 days before I was told this). I just feel like I have more issues going on than what I've already been diagnosed with and want to ask the right questions when I have a consultation with my doctor Monday. We have to move to IVF and I really want to make sure all my issues have been diagnosed and addressed before we invest in something like that. Wishing I could afford to go to one of the best clinics in the country but there isn't anything great around me in Cleveland.