Managing Work while Grieving

I began to miscarry Sunday (one day shy of 7 weeks). I am still physically bleeding and emotionally devastated. Obviously I need time to heal and don't know when I will be physically and emotionally ready to return to work. I am finding it difficult to know how to convey this to my employer as no one knew I was pregnant and I don't want to tell them of my loss. Can anyone share their experience of how you made your return, and how you explained your absence to coworkers?