When you are first listening to calibrated headphones or speakers, it is highly recommended to begin by listening to some music you know well. Chances are, by listening to your own music, you have already compensated for your room inaccuracies in your mix, making it sound unusual if calibration is applied.
So let your ears get used to the corrected sound of your system by listening to other peoples' work for a while.
When you have become fully accustomed to your new corrected sound, you can try bypassing the plugin to to hear the inaccuracies your room was causing before. Use the blue Calibrate button in the plugin to retain the same loudness levels when A/B listening.