TTC after miscarriage

I'm TTC after 2 miscarriages. My boyfriend is supportive of whatever I need and just keeps saying he wants a kid with my but doesn't want me to lose my marbles since I've gone through a lot. We have an appt mid Sept with fertility specialist but more that I read they may not find anything "wrong" with either of us. Not to get too graphic but the first miscarriage didn't all connect so that was just rude on mother nature's part but the last one was very real. I'm trying to stay positive and if we do get pregnant the fertility specialist can still run tests. My doc thought maybe I need progesterone to make it stick but I don't have any signs of it being low so I think just abnormalities during development beyond my control. Anyone else have a similar experience? Should I be waiting on specialist? My worry on waiting is they won't find anything and it might take us awhile to get pregnant this time. Last time was 2nd cycle of tracking. Any thoughts?