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It may be that you're so focused on looks today because of the mood swing caused by missing the antidepressants.
There will always be someone in the world who's prettier, has a better body, etc. Comparing yourself to someone in your family will just keep all the other comparisons alive too...and that's caused a lot of trouble for you in the past.
You are the only one who is paying this much attention to how you look--no one else is saying that you don't have value because your hair's a little too shot. Yes, you do have more value than how you look, and in the grand scheme of life's problems, too-short hair is pretty low on the list.
This would be a good day to write a gratitude list--things are really going quite well for you right now. Why not just enjoy that fact? Change where you are focusing your attention, and accentuate the positive.