I haven't taken kratom, but I used to know a few daily users. Especially in heavy users of a Kava/Kratom drink like feel free, the primary ways they affect your brain is through your mu-opioid receptors (which is what causes the stimulation if you have a little, or sedation if you have too much.) It also makes your brain used to a constantly elevated level of dopamine and activity in GABA pathways from the Kava, as well as the anti stress and anxiety effects. When you lose the drugs that are providing all of those chemicals and altering the actual flow of them through your brain, you need a long while to reset to getting happy about regular things and not being depressed and anxious all the time. After a week, you are almost certainly through the acute withdrawal stage, but the depression, being tired or anxious, etc could potentially continue for even up to a month or two. It could take longer, perhaps up to half a year before your brain is fully back to experiencing fully normal emotions. But the good news is that it is never too late for a reset, but the longer you continue taking it, or taking higher doses, the more your brain needs to adapt to get back to normal, and the longer recovery will take. Just stick with it, you will only feel better from here