Get help. You'll learn better and faster how to deal with specific stresses if you find people to help you who know it themselves. Same with disorganization. Organization is about using systems. Find someone with systems and let them teach you. As to motivation, that's about desire and fear. Figure out what you do and don't want, when it comes to running your life, and you may find the motivation you ne.
Eval/Counseling. Set up small, achievable goals to help you with sense of accomplishment. Involve help of friends/family. Look at what helped you in the past to stay organized, motivated. Practice self-care -- routine, sleep hygiene, relaxation, exercise, proper nutrition. You can also enlist the help of psychologist to help you with symptoms and to guide you through the process. Good luck!
No sadness or stress, just extreme lack of motivation to do anything - even the things I once enjoyed. Is my add causing this or is it depression?
Could be. Depression can present with lack of motivation but usually will have other symptoms like hoplessness and sadness. Add may cause lack of concentration and restlessness and hyperactivity.
It sounds like. Depression. If attention deficit is interfering with your life for long enough it could lead to depression or it may be a separate issue. See a psychologist and or a psychiatrist to sort out what is leading to your lack of motivation.