I am so sorry. I lost 2 between my first and second DD- both at about 16 weeks. 13 years later I can acknowledge that they were not meant to be, but boy was it hard. My youngest 2, ages 6 and 7, call those babies our angel babies. We have special angel ornaments on our Christmas tree to remember them by. My youngest DD believes that our angel babies watch over us and take care of us. She tells me that they weren't meant to be "earth" babies, but are our guardian angels. Out of the mouths of babes!
Remember to grieve. This WAS a child. Don't feel bad about grieving- you have every right to feel a tremendous loss. Time doesn't really heal, it just numbs you a little and helps you put things in perspective. Go to Disney, enjoy your 4 year old and your DH's company. In a way, life goes on, but differently.
We will keep you in our family prayers. God bless you. I am sure there is a special angel in heaven looking out for you- and I am sure you are well protected.