So scared - referred for transvaginal ultrasound

So, I came off Mirena in April and had two regular 5 day/ 28 day cycle periods. Then the next period was a week late and really just spotting for three days. All pregnancy home tests are negative so went to doc and she said I’m probably not pregnant but wants a TV scan done to check what’s going on. I’m scared I’m infertile or something is really wrong.

Having all pregnancy symptoms but no postive test.

Any advice / help / experience??

Thank you xx