Mental fatigue

Hello, I have a very powerfull mental fatigue that starts in the second half of the day.
I will give a simplified view of a normal day, hoping someone will see a pattern linked to my mental fatigue.

I start the day with (1), I wake up with no fatigue. After that it is (2-5) and 1h-2h of (11). Then
I do 3h of (11) and (6).I am now heading home still no fatigue, I get home I do (2-5). I do 1-2h of (11),
after this fatigue kicks in I do (9) and (7). I alternate (11) and (8) to end of day. I end with (1).
Through the day I do (10) in 250ml takeins.

My actions are generally continuous, this is really all I do in a day.

Even with all the discipline, I still can't eliminate the mental fatigue. Please help.
Thanks for the answers.

1.Sleep from 12:00AM to 6:00AM.
2.Eat generally yougurt, fruits and bread.
3.Suplement with ~100mg Anhydrous caffeine, ~10mg L-tyrosine.
4.Proteins suplement.
5.Multi-Vitamin and Mineral suplement.
6.Work-out 2h a day, [1h,1h30min] weight lifting, [30min,1h] cardio. (7 days a week)
7.Cold showers to lose some mental fatigue.
8.Pushups to lose mental fatigue.
9.Instant coffee ~12.8g.
10.Drink 3l-4l of water.
11.Mental stuff ~12h. ( in general it refers to me studying mathematics )

[Dragos_]

I know when my fatigue sets in because it comes with the feeling that my eyeballs are crushed inside my skull.