Generally, a medication such as Cymbalta should reach its full level of efficacy after about a month of taking one steady dose of it, this is around the same time that the side effects usually start to taper off in severity, until they virtually disappear. Other side effects may include increased thirst, joint/muscle pain, and loss of appetite.

How Long Does it take for Duloxetine to Work?

"Sleep, energy, or appetite may show some improvement within the first 1-2 weeks. Improvement in these physical symptoms can be an important early signal that the medication is working. Depressed mood and lack of interest in activities may need up to 6-8 weeks to fully improve." [1]

However, given that it is making you miserable, you should not have to continue taking it, there are other medications that you can try. You should consult your doctor, again, and if they are not helpful, it might be time to consult a different doctor for assistance. It might even be necessary for you to take a couple of medications to treat these symptoms, many people do, and there is nothing wrong with that. While finding one medication to treat several conditions can be a boon to convenience, as well as a money saving measure, not every medication works for everyone that tries it.

Are you on any other medications?