Flickering, dimming. The circuit breaker(s) are either on or off. 
Sounds to me more like a loose connection somewhere, hot or neutral lines.  If it is affected two different circuits after the breaker, it would be in the supply to the breakers or in the neutral bar.
If your not comfortable working with 120volts get someone who is.  
check to make sure ALL screws on neutral buss bars are tight. or all connections in all boxes on the circuits.
Yes leave the breakers OFF until rectified.  Flickering dimming will cause circuits/connections to overheat arc, leading to bigger problems.
Ken