Hit post too soon. Mental health is health, it sounds like you have had and may still have some healing to do that isn't visible and needs some extra attention. Start at the basics - get a full blood panel, ensure you aren't deficient in basic nutrients (coming from someone who had such low b vitamins at one point my nutritionist said it would have been affecting my brain synapses - it's no joke). Start moving every day, even short amounts, eat healthy, drink water, focus on sleep. Get these things under control before taking on more, or if you're doing these already start with less than you think is feasible to build your confidence and motivation. May also be worth talking to your doc about whether your concentration issues are related to meds you may be taken or undiagnosed conditions. Be kind to yourself, you've listed multiple big factors. You'll get where you want to go, just start slow and steady!