Sometimes when certain alters switch out it feels like the bottom drops out, the ambience changes, or even physical changes as in heart rate and pressure because each alter has it’s own unique feel and even combined. In our system, a group is usually present sometimes big sometimes small...and when one leaves or another joins...things feel differently. So, everyday or times I get that “off” feeling, it’s most likely because parts are missing over actual physical conditions, unless there is an actual tangible explanation of physicality.