Like the others said, this isn't unusual for the orientation period. You WILL be forgetting some of what you learned, no doubt, and don't freak that you're a mental defective of some sort when you do
Find a rejuvenating activity on your days off: hobbies, exercise, reading, socializing, playing with pets, whatever recharges your batteries.
Then go back for more! And you will one day be writing the same bit of advice to a new grad yourself
The following members say Thank You: