Thank you man for your time, I guess I got the problem that I had.
And plus to that, I used time_step probably too much, as you've said

Here is the fixed version, is anyone will need this (with your first solution):
// get input:
camAccel.pan -= mouseSpeed * mickey.x;
camAccel.tilt -= mouseSpeed * mickey.y;
camAccel.roll = 0;
// accelerate angles:
my.speedPan -= ang(my.speedPan - camAccel.pan) * 0.8 * minv(time_step, 1); // 0.8 is friction
my.speedTilt -= ang(my.speedTilt - camAccel.tilt) * 0.8 * minv(time_step, 1); // play with it
my.speedRoll -= ang(my.speedRoll - camAccel.roll) * 0.8 * minv(time_step, 1);
// rotate camera itself:
camera.pan = my.speedPan;
camera.tilt = my.speedTilt;
camera.roll = my.speedRoll;
Thank you once again for your time and help!

I appreciate it!