Thank you for trusting JustAnswer with your important question.
Going off a psychiatric medication such as an antidepressant that you have been on for that long (and 14 years is a VERY long time), the longer the withdrawal symptoms are going to last. It is not uncommon for people to have intense withdrawal symptoms for the first 4-6 weeks, with residual symptoms (such as sleep difficulties) lasting 2-3 months.
The withdrawal symptoms are difficult. Usually the first two weeks of symptoms is the body cleaning out the medication from your system. The next two weeks is your body trying to adjust to the medication being gone. Depending on dose and length of time taking, the body can have several weeks of adjusting to the lack of medication and getting used to it's own natural supply flow of neurotransmitters again. This is normal.
Using medications in low dose to help temporarily deal with the withdrawal symptoms is wise. Many people use something to help with sleep (since that plays such a huge role in helping regulate mood and energy), nausea, or dizziness
that withdrawal can cause. Keep focusing on getting adequate rest, eating a healthy diet, drinking plenty of water to stay hydrated, and pacing yourself (you may not be able to do as much as you normally can during these few weeks, take it easy, like you have the flu, and give your body time).