Monitoring DC motor/generator

Hi everyone,

I am using an Arduino Uno and I need to measure the voltage and current from a DC generator. So far no problem with measuring the voltage but when I'm trying to measure the current something funny happens. I put a small resistor (2Ω) in parallel with the voltage divider in order to measure the voltage drop across the resistor and convert it to current but I lose too much voltage in the voltage divider. How can I measure the current and voltage without affecting each other?

Current shunt resistors go in series with the generator, not parallel with the load.