The reason for this longer depression and insomnia symptoms is because Tramadol, besides affecting the opioid receptors, has an effect on the serotonin receptors in the central nervous system. That means you may also need an SSRI antidepressant (such as the
Zoloft that you recently were on) to deal with some depression that may develop as the result of your withdrawal. But it does get better and better every day if you stick with it, so please don't give up.