R.-
Your situation is very similar to mine when I suffered a miscarriage. I had two daughters close to the same ages as yours, and was about 9 weeks along when I miscarried on Christmas Eve. It was a very difficult time for me. I cried for the entire night when the doctor confirmed what I already knew was coming. The really difficult thing is you are still pregnant and hormonal when you find out you are going to lose the baby. The hardest part for me was I still had to be mommy to my daughters while I was grieving inside. It will take you a while to get back to your normal self, but you'll get there. The few months after it happened I found myself crying over things that I normally wouldn't,even though it had nothing to do with my loss, and I know now that I was still mourning.
I took comfort in telling my friends about it when I was ready and talking with others who had suffered a miscarriage. I felt better knowing that I was not alone and you would be surprised how many people have been through this same thing. One fifth of pregnancies unfortunately end in miscarriage, so you probably know a lot of people who have lost a baby, but it isn't something that comes up in conversation. I didn't know how many others I knew until I started sharing my experience - most of my friends have suffered such a loss.
We all deal with things differently, but it has now been almost two years since my miscarriage, and it is not something that I think about too often. It doesn't make me cry to think about it,even though at the time it seemed like my whole world was crashing down. I really feel, in my case, that things worked out for the best. I was able to get pregnant again soon afterward and had a typical pregnancy which resulted in my third beautiful daughter.
I do believe that God has reasons for everything and some of them aren't known to me yet. It may sound crazy to some people, but I am actually thankful that I experienced the miscarriage. I certainly didn't feel that way at the time and I definitely wouldn't want to go it again. However, I took a lot of positive things from the experience once it was behind me. The support of my husband helped me to feel even closer to him. I can better support friends who go through this because of the empathy I now have. Maybe someday one of my daughters will have the same unfortunate thing happen to her, and I will better be able to give her the support and understanding she needs, having been there once myself. It really strengthened my faith,as well.
I think that you will find yourself feeling a little better as Christmas draws nearer. Time really does help, and you are still so close to it. You might want to plan a little alone time, as you need it, to let yourself think/cry, whatever you need to do. I think you will find yourself to be stronger than you realize and be able to focus on the joy of the season for the sake of your other children. No one will judge you if you need to run to the bathroom to cry, though :)
Let us know how you are coming along. Bless you and your family in this difficult time.
J.