Yes, allergies can make you feel tired, weak, and sick. When your body is constantly fighting off allergens, it can lead to fatigue and a general feeling of weakness. The release of histamines and other chemicals during an allergic reaction can cause inflammation and discomfort, contributing to these symptoms. Additionally, symptoms like nasal congestion, runny nose, and itchy eyes can interfere with sleep quality, further exacerbating fatigue. While allergies typically don't cause fever or severe body aches like the flu, the overall impact on your body's energy levels can make you feel unwell.