Late period after miscarriage

I had a miscarriage on June 6 at 9 weeks, the bleeding lasted about a week. Afterwards, my next cycle came on July 9 and last about 4-5 days (like a normal period). Now it's August, I should have received a period around August 10th but it is now August 21 & I have no signs of a period. No breast tenderness, just some slight cramping & a little bit of acne. What should I do about this missed period? It usually comes like clockwork & doc says I have to wait til I miss 2 periods to be seen about it.