One of the things that may have surprised you after the loss of your child is the variety of emotions that you experience. You may experience shock, anger, sadness, guilt, or even a sudden attack of the giggles. These are all common emotions that most people experience after a loss.
Most I think are surprised to feel anger. This seems so astounding but is very common. "Why did you leave me?" "Why God did you take him/her?" Then our anger becomes compounded by feeling guilty about feeling angry! Just know that this is natural and will subside with time.
As far as the giggles. It is not uncommon when you are under a great deal of stress for your body to let off some of that stress with a case of the giggles. Again, this is not uncommon. Remember the old saying "laughter is the best medicine"? There is actually research that confirms this!
Give yourself and others a lot of latitude when dealing with all of the emotions that you and they are bound to experience. Some wise person once said "Feelings are not right or wrong, they are just feelings".