If you’re feeling low energy, start with the obvious: where you’re exerting your energy. If you have a lot of social obligations and a long to-do list, you’re going to want to prioritize. Consider things you can put off until you’re feeling more up to it. If stress is one of the things eating away at your energy, think about keeping (or making) plans with people that you can talk to about those stressors. Letting the bad stuff out is as important as getting the good stuff in.
Now for that good stuff. Do exercise even if you feel you don’t have the energy for it. When you workout your body releases epinephrine and norepinephrine. These are stress hormones that in small amounts can energize you. You don’t have to go nuts either. We’re talking even going for a walk, especially a walk outside, as exposure to nature plus physical activity has been proven to boost energy levels for longer.
Finally, food. When you eat sugary or high-starch foods, your body absorbs them quickly and doesn’t get long lasting energy from them. So low glycemic index foods is what you should be eating. These are the ones that have sugars that absorb more slowly--whole grains, high-fiber veggies (google it, there’s so many), nuts, and olive oil are all your friends.
Oh, and drink lots of water ;)