Period regularity after miscarriage

On the 13th of April I had a D&C I bled for about 4 days... I then waited 28 days until the 11th of may and I had a 7 day extremely heavy period. My cycles are normally 31 days long. I'm now day 35 and I still haven't had my period. I took a pregnancy test on day 32 and it came back negative. I had sex 2 days after my last period. How often do you have a period after a miscarriage, should it be regular or should I wait and take another pregnancy test? I haven't really had any symptoms but frequently urinating and a very sore back.