Clear signs of purification are things like repeatedly dreaming of flying in the sky, wearing new clothing, vomiting out bad things and so forth. These are considered good signs when they occur repeatedly. Bad signs are for instance if one sees a temple or monastery and so forth but it is not so nice or one meets the lama but he has a sad face and isn’t beaming. Another example is the sun setting. Also when one has strong negativities it is said a sign of purification is one gets sick, etc.
~ Geshe Tenzin Tenphel, commentary on the Treasury Of Manifest Knowledge (FPMT Masters Program)