It sounds like you need some career counseling, some motivation, and maybe some antidepressants!
I do have an MBA.
It was fun to get and a great experience. I got it from a state school after work. It was very affordable and took considerable time and effort.
I don't use the letters MBA after my name and most people wouldn't guess that I have one.
I have heard it said that you should not tell people you have an MBA - just use what you learned.
An MBA will not be a ticket to anything.
Harvard MBA? You got into Harvard without a Harvard MBA. That's where your strengths lie. The Harvard MBA is just icing on the cake that you already have.
Here's my advice:
Read some books on picking a career. "What color is your parachute?" is a classic.
Get motivated!
I really like Brian Tracy tapes (MP3's these days. I have been doing this for a long time.) Google for them. Check out Nightingale Conant products. I warn you - these things will fire you up but the feeling wears off fast. You have to keep them going almost every day in the car, while exercising, etc.
Get healthy. Eat right. Exercise. Yada, yada, yada.
Sounds strange but journal every morning.
Write down - don't just dream - write down what you are looking for in life, what your ideal job would be, what you would do if you didn't have to earn money to live. What do you want to contribute to the world?
What are your natural gifts? Are you exceptionally smart, good with numbers, good with people, a born leader, physically attractive, creative, artistic, willing to accept uncertainty, persistent?
Do what you love and the money will follow. I'm not so sure. But do what you love and live within your means and happiness and satisfaction will follow.
Print this out right this minute and read it every morning for 100 days. Put it by your toothbrush.
Learn to have a positive attitude at all times. It takes practice!
Report back.
Good luck!!!!