Very discouraged about not getting pregnant

Me and my hubby have been TTC for a little over a year now. I do have two children ages 5 & 7. I got pregnant with both of them by accident and very easily both times. I have had two miscarriages since. We want another one but cant seem to get pregnant. I have been diagnosed with a blood clotting disorder which could play a role in both miscarriages and also a chromosome abnormality. I've been really down about it lately and coming to terms that I may not be able to have another one. Its making me very depressed. Any words of wisdom?