I would have your doctor check for scarring. That is a real possibility after a dnc (although they will tell you it is very rare...blah blah blah). I'm not saying that is the cause, but it very well could be. They could to a saline induced sonohystogram to rule it out, as a regular u/s will not show scarring. Also, if your cervix is scarred, blood may not be able to exit. hense the premenstal feelings, but no period.
Please let me know if I can help in any way!
Call you GYN/OB is you haven't already and ask. This is something he or she may want to know.
It may take you a few cycles to get back to what is normal for you. I had a m/c at 6wks but didn't need a d&c and it took about 2 cycles for af to be back to normal for me.