If you haven't had some diagnostic testing done by a physician yet, I would suggest doing so. That way they can rule out cyst, fibrosis, hormonal or blood issues. Setting those aside, if you are otherwise completely healthy, it is probably a psychological issue that is stopping you from getting pregnant. A miscarriage can cause a lot of emotional stress and sometimes even Post Traumatic Stress Disorder (PTSD), even if the miscarriage happened in just a few weeks or months of the pregnancy. Take some time to go through your thoughts about what happened, grieve again if it feels right, and really examine your deepest feelings about everything. Then go back at it with a positive mind frame. Otherwise your body will not let you conceive, because it will sense that it's not the right time until you have healed.