Thanks for your help & suggestions.
You can talk to the psychiatrist who gave you your medication, and ask about the side effects of your hands trembling and perhaps the panic feelings, and maybe he can substitute another medicine in the same class as the one that might be bothering you.
But as for your job performance, I would say that there is a possibility that the failed relationship you had is unresolved in your mind, and thus you need to talk with someone about all this pent-up frustration that you cannot seem to deal with. It is coming out in inappropriate ways, making you feel like giving up, making you feel angry. The psychiatrist can recommend a psychologist, these are people who can spend far more time than the psychiatrist in talking with you, to help you identify the source of your frustration, give you help on how to deal with it in appropriate ways, and offer you moral support.
In the meantime, you are becoming focused too much internally because of all these emotional problems. A good way to release pent-up stress is to get involved in a physical activity, even ordinary running a mile or more several times a week, will help, taking up tennis with a friend, or study self-defense. Also, you have got to find something to do in your spare time away from the office that is totally different than what you usually do, everything from sedentary stuff like learning how to play guitar, or taking up painting, all the way to complex interests like getting involved with volunteering at a hospital, or helping people rehab houses for needy people, that sort of thing.