so I had a miscarriage October 19

I had a miscarriage October 19 and my husband and I have been trying again since we got the ok from the doctor.. I have been spotting for the last 4 days.. when should I take a test? And the last miscarriage was due to the rh factor.. I am a negative and my husband is a positive.. could I be seeing this happening again.. I have had the shot for it.. or could this just be my body trying to recover from the miscarriage.. me and my husband have been trying for 5 years and that was the first time that we have been pregnant .. so we have been hit hard in the face.. we don't want that to happen again!! Help please! Thank you in advance