I honestly don't know anything about the physical symptoms you described, but I do know about depression.
First of all, its good that you have come here. Emotions are like a raging river, and the skull is like an overstressed dam. The best thing to do is let it all out. If you your mother or your doctor won't listen, you feel worse. But you can also do that here. Even if we are not face to face, telling someone does help.
Secondly. "All this optimism I have built up is a lie" that is only true if you believe that it is true. and what you believe about yourself can change in a split second.
this might not help, but I would like to share with you, some words that one of my prfessors shared with me, that I have never forgotten, that helped me through some difficult times.
LIVE A LIFE THAT MATTERS
Live a life that matters.........
Ready or not, someday it will all come to an end.
There will be no more sunrises, no minutes, hours or days.
All the things you collected, whether treasured or forgotten, will pass to someone else.
Your wealth, fame and temporal power will shrivel to irrelevance.
It will not matter what you owned or what you were owed.
Your grudges, resentments, frustrations, mean spirit and jealousies will finally disappear.
So, too, your hopes, ambitions, plans, and to-do lists will expire.
The wins and losses that once seemed so important will fade away.
It won't matter where you came from, or on what side of the tracks you lived, at the end.
It won't matter whether you were beautiful or brilliant.
Even your gender and skin color will be irrelevant.
So what will matter?
How will the value of your days be measured?
What will matter is not what you bought, but what you built;
not what you got, but what you gave.
What will matter is not your success, but your significance.
What will matter is not what you learned, but what you taught.
What will matter is every act of integrity, compassion, courage, love or sacrifice that enriched, empowered or encouraged others to emulate your example.
What will matter is not your competence, but your character.
What will matter is not how many people you knew, but how many will feel a lasting loss when you're gone.
What will matter is not your memories, but the memories that live in those who loved you..
What will matter is how long you will be remembered, by whom and for what.
Living a life that matters doesn't happen by accident. It's not a matter of circumstance, but of choice.
Choose to live a life that matters.
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What is learning? Its paying attention. its opening yourself up to this great big ball of****that we call life! And whats the worst that could happen? You get bit in the ass! Well let me tell you, My ass looks like hamburger meat,But I can still sit down!