Have you looked into your diet? I can always tell the quality of my breakfast while hiking/biking. If it's my regular smoothie breakfast (berries, bananas, spinach, oats, flax, protein powder, peanut butter, fresh ginger and turmeric), or sometimes just a fruit smoothie and a bowl of peanut butter oats and grains, I can work those hills like a champ. If we decide to spend the night at the trail head and instead go for a store-bought protein bar and a piece of fruit, my boyfriend and I can always feel it. Same as with biking, if we stop for breakfast on route, (eggs, toast, hash, maybe some grilled veggies) it's always more difficult. It's crazy because we even noticed that it doesn't matter what you do the night before, or how bad you sleep, as cliche as it is, it's all about the breakfast.
Just a thought