I suspect you have your test meter, when in mA/A mode connected between the +5v and ground. This places a virtual short across the supply.
Basically current flows "along" a wire so when measuring current you need to place the meter into the current flow. You achieve this by connecting your supply voltage + wire to the meter + terminal and you connect the meter - terminal to device + terminal.
Voltage is measured by setting the meter to volts and connecting meter + terminal to the point where yo wish to measure and the meter - to the device ground point.