A Restless Heart
If you find yourself in a situation you are not comfortable in (i.e., a "job"), chances are you are not where you should be. Feeling perpetually sad, insecure, grouchy, or any other negative emotion, for no apparent reason could be your spirit telling you that all is not well in your world, much like pain is the signal to the brain that something is wrong with the body. When people make remarks to you like, "Oh, it's just your imagination," "you're too sensitive," or one I used to get a lot, "you take things too personally," pay heed. This could signal you are leaving the path of conformity to search for a better purpose for your life, and people don't necessarily like that. It is an unfortunate fact that most people in general will try to hold you back. Not because they are mean or jealous necessarily; but fear of another's success causes some others great discomfort. It often makes them feel that their own lives are inadequate, and one of their master strokes of manipulation to get a non-conformist to conform is the use of the foregoing comments and others like them. In short, you are a threat to them.
Do not listen!
There is an unwritten law that if you want to succeed in life you must separate yourself from the pack. This is true. The first step is to get away from all negative people -- those toxic individuals who would rather see you fail. There is a lot of them out there. Maybe you can't put actual distance between you and them (some of them might be within your own family) but you can limit their influence. Surround yourself with books and articles of self-reflection and improvement. Lift your spirit up by reading about the great entrepreneurs and inventors of history: Edison, Bell, Ford, Curie, and so many others, their lives, and the obstacles they had to overcome. And try to keep yourself to yourself, that is, keep your dreams, desires, and aspirations to yourself and share them only with those you would trust with your life, who absolutely believe in you.
Visit your inner sanctum often, it is your place of power and creativity. Spend at least fifteen quiet, uninterrupted minutes a day in self-reflective meditation (an hour would be better). Remember the old adage: Silence is golden.