If you feel run down you need to work out what you’re not getting.
Protein- you should be aiming for 0.8g per kilo of body weight, for me that’s 50g per day. It’s easy to get but you do need to think about it sometimes. I buy coco crunch nakd bars which have 5g, bread has about 8g per slice, peanut butter about 3g per 12g serving, kidney beans about 8g per 100g (about half a tin) etc try and have at least one serving of pulses (kidney beans, butter beans, chick peas, lentils etc) every day.
Iron, calcium- again pulses and green leafy veg, nuts, seeds for iron also dried fruit and whole grains like oat, quinoa and brown rice also most bread is fortified with it. Have a source of vit c with it like tomatoes to improve absorption and not with black tea as it reduces absorption.
Zinc- nuts seeds pulses and whole grains
Selenium- Brazil nuts, seeds, pulses, green leafy veg, whole grains.
Vit D- sunshine or fortified foods or a vitamin tablet/ spray.
Vit b12- fortified foods or vitamin tablet/ spray.
Omega 3- flaxseed, chia seed, coconut oil, rapeseed oil, walnuts, hemp seeds, Brussels sprouts or algal oil supplement.
I’m not a dietician but long story short it seems a diet high in a variety of nuts, seeds, legumes, green leafy veg, whole grains and with some fresh and dried fruit should cover you for most things, if you’re already eating that then speak to a dietician.