Amoxicillin does not typically make you sleepy. In many cases, sleepiness is caused by the infection being treated by this antibiotic. Fighting an infection can wear down the body and increase energy demands.
If you think the sleepy feeling may be related to the medication, the best option is to see your primary care provider or talk with the healthcare provider who prescribed it. They can evaluate whether your sleepiness could be a reaction to amoxicillin or if there may be another cause.
The most common side effects of amoxicillin include diarrhea, nausea, and mild skin irritation.