I'm certainly no expert on miscarriages (had 4 uneventful pregnancies -- except for severe vomiting). I have heard, though, that a miscarriage early on means that something was probably quite out of the ordinary and it's 'nature's (AKA God's) way of taking care of things. If it's something that you can't do anything about either way, just place it in His capable hands.
Try concentrating on your 2 healthy children, your husband, home, and job. If anything is true, honest, just, pure, lovely, of good report; if there be any virtue, and if there be any praise think on THESE things. You won't have time to worry or fret so much!
It's so easy to lose sight of our blessings in the midst of turmoil, but God WILL allow what's BEST to happen if we'll kind of stay out of His way (if you know what I mean!) His will isn't always for things to go smoothly, either; but His greatest works can be done amidst the worst happenings (as demonstrated in the 9/11 terrorist attacks and many other examples). In other words, His ways aren't always 'fun', but they ARE always 'right'.
God bless!