I’m always exhausted.

I am a healthy weight (50kg) and 5"6. I don’t eat any sugar, white bread/ pasta, dairy or junk foods.

In a typical day I would eat:
Breakfast: Oatmeal with soy milk and some fruit
Lunch: 3 boiled eggs and slice of wholegrain bread, some tuna on toast and maybe a salad
Dinner: Medium salad, cooked salmon, chicken or a steak (I also take a multivitamin and fish oil at dinner)
Drinks: Only drink maximum of 2 alcoholic drinks when I’m out and don’t drink coffee, tea or softdrinks just water and herbal tea.

I am not very fit but I try to exercise every second day – running on treadmill for 25-30 minutes or exercise bike for 30-40 minutes.

I don’t know what I’m doing wrong but I’m always really tired. Any tips?