"To lose respect for someone" or "To lose self respect." Both means losing respect, but the former is for someone else, and latter for yourself. For example, after what he did, I lost my respect for him. OR After failing the test, I lost all my self respect. Hope it helped:)

Typically, the phrase is "lose my respect (for) (sth/smb)" or "lose my self-respect". The first one means that you used to respect a person or thing and now you don't. You don't respect it/them anymore. To lose your self-respect means that you don't respect yourself anymore.