Period after D&C

Loni • My name is Loni & I am 22 years old. I am a single mom to a 3 year old son. I have hypothyroid, PCOS, MTHFR, PAI-1 & Protein S Deficiency. (Currently pregnant!)
When did you get your period after your d&c? It's been almost a month & still no signs of Aunt Flo. When should I be concerned?