Going back to work..

So tomorrow I go back to work after having 2 weeks off to have my miscarriage. Only 2 people at work knew I was pregnant but now I've miscarried I told my bosses so they know but others at work don't. I'm worried as to what to say to them when they ask why I've been off for 2 weeks. Do i lie? Or do I just blurt out that my baby died inside me and I had to give birth? I don't want them all to think I've been off because I was just 'ill' it just so happens to have happened over our busiest time all year at work too so everyone has had to work extra hard and cover all my shifts too.