Trouble getting pregnant after miscarriage

I have 4 healty children all boys..So of course I long for a daughter. About 2 years ago I had a miscarriage. I went through labor to deliver the fetus but they didn't get everything out so I had to get a DNC which I was trying to avoid. I never had fertility issues before but I still have not conceived since then. They did a dye test to ensure my tubes and paths are clear and they are but still no conception. I am getting closer to 40 and starting to worry I will miss out on that window. I don't want to seem selfish because I already have 4 healty kids but I have to say I long to have that one more. Has anyone had a similar experience after a DNC?