Welcome to Just Answer and thanks for your question. The symptoms you have experienced - difficulty concentrating and with memory, palpitations and rapid heartbeat, shortness of breath, lack of appetite, chest pain, irritability, and the others - are typical of anxiety disorder. It takes a minimum of a month for any anxiety or depression to work, so don't give up on them too early. It also can take a year or more for cognitive behavioral therapy to help a patient deal with their disorder can begin to help, so don't think that the psychiatrist or a psychologist have failed yet either.
By the way, the only way it is physically possible for anyone to lose weight is to take in fewer calories through food and drink than they expend in exercise and metabolism. The anxiety and/or depression was probably the reason for the weight loss.
what about the nausea though? it hurts and makes me nauseous just to cross my arms. its too much pressure on my stomach. i've been to a g.i. doctor and he gave me a prescription version of prilosec which didnt help at all. he told me i had a spastic stomach but didnt do any tests at all. he simply felt my stomach. when i try to sleep at night, i cant lay on my side anymore cause i can feel all my organs shift when i turn