to restate something already said by someone else — go and get a blood test to check that you don't have any deficiencies! iron deficiencies are veryyyy common, or you could even be low on iodine (which can be figured out by getting your thyroid levels checked), vitamin d or vitamin b12. and even if you find you're not deficient in anything supplements and probiotics can still be a really good idea.
it also cannot be understated how beneficial being outdoors in the sunshine is. if you can start your days with a walk, even if it's ten or so minutes that does a lot of good. a consistent sleep routine and not eating too close to bedtime helps. make sure you're getting lots of protein and not consuming too much caffeine. i also hate to say it because i'm anti-breakfast, but eating in the morning is actually really good for you, your energy, and your metabolism. can be an egg on toast (protein) or fruit with oats and yogurt (protein, prebiotics, and probiotics).
hope you start to feel better soon! <3
