You are most probably experiencing right hand roll due to asymmetrical loadout causing one wing to be loaded heavier that the other.
This happens often, and you are expected to compensate with trimming.
You will find yourself trimming during almost all aspects of flight. For example the following things off the top of my head will cause you to trim/re-trim: Speed changes, after weapon release on one station, after engaging the GUN/PAC System, after structural flight surface damage, etc.