Life after loss.

I miscarried on the 15th of September. Almost 3 weeks later, I feel as though life is completely normal again, at least on the outside. I still have a crazy 4 year old (adopted) to chase around, a husband and a home to take care of, but the bitterness and sadness is still consuming me on the inside. We tried so hard, I fought so hard to concieve and carry that baby, how is that something I just get over? I have no motivation to do anything remotely enjoyable or for myself, because I feel so guilty. I'm worried about how this will affect my son, and my marriage, if I can never get over it.