Was doing some thinking, particularly about the phrase “I’m not feeling like myself”... 

I realized that doesn’t make sense to me because I don’t know what my normal self is like. I feel like I don’t really have a consistent “self”? I don’t know what I’m like when I’m not like... this. Am I supposed to be my moods? My moods change so fast and how I act depends on my mood. My highs seem foreign and so do my lows but the lows are so common and have been so consistent in my life for so long that there is comfort and at least some familiarity. 

I know what I’m like when I’m sad/upset. I know what I’m like when I’m happy. But none of those feel like me I guess.

Is this what is meant by the symptom “unstable sense of self”? Does anyone else relate or am I overthinking this?