strattera making me exhausted?

i’m new to taking strattera, it’s around my fourth day and i start at 40mg. i’m prescribed to take it daily in the mornings but i dont know how much longer i can go at it. it makes me feel soso exhausted. i feel like my body isn’t getting enough sleep and it impacts how i act at work and how i am for class. theres points where i dont even know im awake and i snap back into reality. is this normal???? should i keep going since its only the fourth day?? ive been napping and i still feel tired. i also cant take it at night because i’m taking fluvoxamine, which also makes me sleepy. im new to adhd meds… any advice????