Stuck on loading terrain

I lost 2 worlds that I've spent a few hours on and can't get on them anymore, i crashed on the worlds and when i tried joining them again it gets stuck on loading terrain, I'm not sure if its on windows but I'm a mac user and it wont load in the world. If you guys can please fix this real quick that would be great cause I still got plans on those worlds and don't want to keep making a new one and probably losing that one as well.