Dear Sarah,
I know how much it takes to "get your head" around your loss & you are right, you will never forget the little girl who was part of your lives for such a brief time. I found it hard to admit that I wanted to move on as I felt that in some way it meant I had forgotten Alex. I came to a point where I decided that I was ok with him being part of our lives for such a short time & that it was ok to want to move forward, he is always in my thoughts & nothing can ever erase the fact that he was part of my life. You will find your own way to deal with it all & if being PG again is what you want to do, then go for it. Katelyn will always know that you care & that if there was anything you could have done to make her outcome different then you would have done it.
As for AF my first cycle after m/c was normal, but my second AF visit the first day was a nightmare! The first day I bled really heavy & I mean really heavy. I was changing a tampon every 2-3hrs & it was soaked. After day 1 it settled back down, thankfully & went on to finish off normally. I don't think it will affect your chances of a PG this cycle, you may just O a bit later than you would have.
Hope things are going a bit better for you & thinking of you.