TTC for 4 months post-miscarriage

Hi - I am new here!
I got pregnant in May 2009 and miscarried in Aug. 2009 at 3 months. They said it was just one of those 'flukes' and it was not my fault etc. I have severe endometriosis and adhesions, so was surprised to get pregnant on the 2nd try!
Now, 4 months post miscarriage, I still have not gotten pregnant. I am trying everything right and seem to be ovulating. I used misoprostyl to miscarry and it seemed to go well, my HCG levels were back to 0 within 35 days.
I see the doctor again next week, but cannot comprehend why it isn't working now! I wanted a baby so bad again and to be pregnant by Xmas, because I am getting depressed as the months pass that I would have been pregnant and almost due.

No google searches or books explain why it would be hard to get pregnant after a miscarriage. I am so upset and wish I had some answers. Anyone?