I think you have to just make these things concrete by asking yourself specific questions. Live in the moment and take an assessment. Have you tried to be a morning person? This probably requires going to bed early and waking up early and probably limiting food after 5pm and caffeine before noon. Possibly limiting alcohol etc... Do you have to commute a long distance to work? Do you like company and seek people out? Do you call people? Do you visit other places? Do you look forward visiting other places? For work, do you find yourself getting irritable, overworked? Are you looking forward to a vacation? Do you have some kind of balance (gym, friends, family?) Do you work 12 hours a day on a project going nowhere? Do you like your work, your coworkers? I also wouldn't say that your personality is necessarily defined by these things either. I think personality has a couple aspects and is by definition multi-dimensional and changeable. It can defined by you to yourself and that as it appears to others. It easy to see personality evolve from little kids to adults. Perhaps you are searching and that's ok. I think you just have to find things that work for you and work for your goals.
