Worth having a go at improving diet. I do subscribe to you are what you eat. Nothing wrong with egg on toast but try and buy decent whole grain or rye bread, make pack lunches to avoid canteen food, big hearty salads with grains and seeds in, if sandwiches make sure it’s something healthy, mackerel, tuna etc on sourdough or wholemeal and some fruit. Dinners max out the veg in your stir frys and curries and have meat free days and fish days. Nuts and fruit to snack on or dark choc. I used to mess about trying different suppliments when I felt sickly but now I just eat a hugely varied healthy diet and make my own bread to avoid supermarket sugary crap. Biggest change to my diet was from subscribing to an organic veg box as I had to learn new recipes to use up all the different types of veg that arrive.