When should I take a test after misscarriage ( for another pregnancy)

Lanie
It's hard to figure out my period since I never had one since my pregnancy. I have not had a period since september 29th I had a 29 average cycle. I don't know when I would have been expecting it. 
 I think I would have been 3 days late give or take. 
When should I start thinking I should be testing for pregnancy?