Here is my take on your situation. I myself am not always a very confident person, often a difficult situations I shy away from standing up for myself only to hate myself later. I have learned that if you act a certain way, that is just go through the motions of being confident then the mind will follow. Acting confident doesn’t take much to do, stand up straight and don’t back away from a person, look them in the eyes but don’t burn them with a scolding look. Keep your face soft and relaxed, allow your muscles to relax. When you talk keep it short and to the point, take deep enough breaths to sustain a clear voice do not rush your words. Don’t apologize or make excuses, if a question is asked that you don’t know the answer to simply say, “I’m sorry I don’t have the answer to that right now, I am going to go do some research on the subject, let me get back to you.” You say you meditate, so I take it that when you meditate you try to clear your head, that won’t help you. Instead try visualization, visualize your boss talking down to you and envision your self brushing it off and it does not phase you, then you display your confidence in what ever way you think fit. Don’t see work that seems too hard or too much get you down, you will get through it just attack it with out even thinking about its difficulty. Too often work we think is hard is made harder and takes longer because either aloud or in our heads we complain about it instead of just focusing and getting to work, once it is done then you can look back and think that wasn’t too bad good thing I didn’t listen to that voice in my head. Everyone has the voice of doubt at some point, but some people don’t listen its up to you whether you listen to it. Also try standing in front of the mirror when you are alone and having one of your “meetings” with your boss, but be confident obviously it is just you and your imagination their is no reason that you can’t feign confidence. Practice this and maybe it will transfer to your job. Also don’t feel desperate in finding a man, I don’t know how many times I searched for something desperately and caused myself suffering and anxiety never to find it in that it in that state, once I relax and stop looking low and behold it seems to find me.
Hope my words can help you,
Mike