Gauges

Ok the gauges are screwed up. The MPH gauge always stays on 0 once ina while it will work but not for long. The RPM gauge started screwing up as well, It goes past 3 and up to the max witch I think is 7 when im only driving like 40 mph. Then the gas gauge was turned all the way back onto th MPH gauge. I dont no whats wrong but the gauges seem to be gettin worse. Im not even for sure how much gas I have anymore because it switches up so much. Can anyone tell me why or have some hypothesis.