SPD or Arthritis?

[sepa]

Evening ladies, wondering if anyone can help with my conundrum.
I went to hospital the other day (Tuesday) as I had reduced movements and pain in my pelvic area. The pain in my pelvis started Saturday night/Sunday morning. The midwife who assessed me at hospital said that she believed that the pain was the start of SPD and that I should get my midwife to refer me to physio.
On Thursday I had a scheduled appointment with my midwife who asked me about my hospital trip and I explained about the pain etc and again she said it sounded like possible start of SPD and would I like her to refer me to a physio. I declined this as the pain wasn't enough to warrant this.
Now (Saturday night) the pain has completely gone.

I suffer with a form of arthritis which hasn't gone into remission and it tends to have pain which can last just minutes to up to a month. As this pain lasted less than 1 week I am thinking that it was probably arthritis pain and not SPD.

I do not know much about SPD and when I have read on the internet it seems to be very painful (where people are using crutches) and lasts until after the birth of the baby. Just wondering if SPD can last for such little time or if it can come and go depending on activity level?