Welcome to iRV2.
Sorry your first post is about problems .
YES , 120 volt circuit breakers can go bad , also loose connections at the circuit breakers can cause issues like yours .
Do you have a multi meter ?
Disconnect from shore power , remove the cover plate in your C/B panel , and tighten the screw holding the wire into the C/B.
Connect to shore power , and check for power to the outlets. If no power to the outlets , carefully ; using the multi meter set to 120 volt; check for 120 volt power at the wire connection of the C/B.
For more help please add ALL your RV's info to your post .