all objects are abruptly disappeared

I inserted a new object in the scene, and maybe i press a taste not wanting, and all objects scene are disappeared! ç_ç took me 3 weeks to make this!
please help me! :((

This is a pic:

Have you tried make double click on any object showed in your Hierarchy panel on the left? It seems to me you are not looking to the objects but they are there anyway. Unity resets the editor view whenever you open the scene.

Also, let me give you two tips:

Use any source code control for save your work! A simple zip taked from time to time can make the work.

If you make any unwanted change on scene use CTRL+Z or simply reopen the scene without saving.

Just to be sure, have you tried to press “F” on Scene screen with any object selected in hierarchy?