Feeling drowsy may be a side effect of too many antibiotics.

Answer: Option D

Dizzy : having or involving a sensation of spinning around and losing one's balance.
Energetic : showing or involving great activity or vitality.
Irritable : having or showing a tendency to be easily annoyed.
Sluggish : lacking energy or alertness.
Drowsy : sleepy and lethargic; half asleep.

Synonym of Drowsy is Sluggish