Multiple sprites into one gameobject.

Hello guys! I built a simple tile generator for my game, It generates multiple tiles gameobjects and sets them in places.

The problem is that each tile is a different game object, and eventually, there are tons of GameObjects in the scene, the verts and tri counter goes high, and it runs very slow.

Here's a screenshot:

is there any way to optimize this? I really wanted to get rid of all these tris and verts, by making them the same GameObject...