MY Milage changed by it self

What is your question?

oil changed 3 months ago , I have driven 3000 miles my next oil change was set for 160,000 on my spedo. but my spedo changed to 256,679 on its own . now I know I have not driven that much in 3 months. and can show all other oil changes the past year or so . what happend? also I have 3 lights that cam up on my dash at the same time. ABS, TC , And a light with a picture showing my truck going down hill with a "line underit" Help