Glad to hear the soreness has eased off. Not sure about the internal but I would think your OB or Doc or Midwife should be able to tell you where your uterus is sitting just by touching the outside of your lower abdomen.
Good Luck, on tuesday, I hope you can find out what caused it. I have my NT scan tomorrow morning, have started to worry over the last couple of days something will be wrong, fingers crossed all goes well.
Have a good Chrissy.