Try not to worry about it so much. Generally, to get a healthy balanced diet, you need proteins, fats, carbohydrates, fibre. A range of fruit & vegetables will give you a good spread of vitamins & minerals, & lots of soluble fibre. Protein can be found in a lot of foods - meat (preferably not too much fat), nuts & seeds, beans & pulses, grains, eggs, cheese, best to eat a range of proteins. Wholegrain carbohydrates, so brown pasta, rice, wholemeal bread, quinoa etc. Healthy raw fats from nuts, seeds, avocadoes, coconuts (basically vegetables). Avoid processed food as much as possible - eat food that looks like it did when it grew, not something from a factory. Don't eat too much refined sugar. Eat some raw food every day - salad in your sandwich, a couple of pieces of fruit, for example.
Porridge is fine. I like the coarse rolled oats personally. Oats are good for keeping your bad cholesterol at a low level. Cow's milk is more natural than soy milk, bit there are other non-dairy milks, eg oat, rice, that can be used in cooking.