Even when my sleep cycle is regular, most of the time I awaken unpleasantly tired. I gain more disposition during the morning, when most of my classes are ministrated, but the tiredness is severely aggravated during the afternoon, when my productivity is nearly useless. Engineering is not a spectator course and in order not to fail I must dedicate a lot of time at home to study, which is merely not happening due to debilitating mental and physical power and short attention spam. My psychoterapist ( CFS gave me clinical depression ) adviced me to low my expectations and focus on not failing in any class instead of having optimal results in all of them, which is impossible in my condition. Are there any other strattegies I could employ to maximize my energy while studying? Natural stimulants didn't work with me. One thing that works with me but is not an optimal solution is to use the time in between classes to study, but it's not enough. Any extra help?