HSG test Scheduling?

Hi all- my doctor ordered a HSG test for me after 13 months of TTC. She said to call on CD 1 and schedule for CD 5-7. My question is, I have been spotting the past 3 days and am afraid I am just having a really light period. Spotting for more than a day before I start isn't normal for me. I'm already late and getting negatives.

Do I just hold out and hope that my period starts fully soon? I am just nervous in general and would like to have the test done this cycle