Blender to Unity mesh issue

Hey all! I exported a 3D landscape from blender as a .blend file and put it into unity. Later I found that although the model is correct (in the right position, correctly scaled, ect.), the mesh of the model is significantly smaller than the model and is also turned on its side (90degree turn on the y axis). My end goal is to have a collider mesh for the landscape, so if it is possible to achieve this in any other way that would be appreciated!

Thanks!