Go to Lowes or Home Depot and get yourself $3 wiring tester.

All you need to do is just plug it in.., and it will tell you if
circuit is not
wired correctly.

I just went around the house and measured the voltage in outlets and
found
that some were at 139 VAC, and some were at the normal 124 VAC.

Not very likely.... Get another voltmeter and measure again...