for instance, the foundation spreading apart can break water lines, pull electrical wires to a stretching point, can cause all sorts of plumbing problems. these things are behind the walls.
Yours sounds pretty severe. You may need foundations jacks installed all around the home to get back to original.
You can have a water level test done which is water in a tube laid over the floor and the bubble or the water level will always travel to the low spots, this is helpful.
Are your comodes draining harder or do you have trouble with a small amount flushing? Do your sinks drain slower than usual? Is your water pressure lower in some rooms than others? Do you see standing or wet soil on the outsides of your home during dry times? All of these are tale tale signs of problems.
This is hard to diag without seeing the problem first hand.