I had this after my 1st mc (i have had 4). I felt so desparate to be pg again, it happened so quickly the first time round, but we had 6 months of nothing happening before calling it a day for a bit. Funnily enough, 3 months being back on the pill, and i caught first cycle after coming off. Ok it didn't go well that time for me, but since then, even with the losses, we have been much more chilled out about the concieving part (probably because thats the bit we enjoy the most, BFPs have become the start of worry and heartache).
There is no evidence for stress being the key thing, but the more stressed i have been and the more desparate to be pg, the more it seemed to elude me. I started doing things again that i was putting off "just in case", and this is what got me to do the magic relaxing thing that everyone tells you to do but not how!!!