@oneboy3girls Rolled oats are perfect. I have them as well some mornings. In mine, I add a tablespoon a grounded flaxseed.
Many have a carb-phobia when it comes to weight control, but I keep a container with black or brown rice and another with cooked quinoa, and I add a spoonful or two to my salads.
There is a big difference between eating a bag of biscuits and a small amount of whole grains.
Soups are also great. Especially in winter. Make your own, I love my tomatoes soup (1 onion, 1 carrots, 1 celery stick, 5 fat and ripe tomatoes, 1 bottle of passata, then fill the bottle again with water, put lid on, low gamer for 45 min, and blend. ) or carrot - pumpkin (1 small kent pumpkin, 5 carrots, 1 onion, add water only to cover the veggies, not have them swimming in water, low flame, an hour on stove and blend). I sprinkle a bit of nutritional yeast on mine for get a lot of B vitamins , but not too much because it is quite high in protein and I am very mindful of my protein intake.
A healthy level should be at around 1 gr/ kg of body weight so if you weight let's say 60 kg, you shouldn't have more than 60 gr of protein per day. Longevity experts recommend even lower level, around 0.8/kg which I follow. I eat around 40-45 gr of protein/ day, and you would be surprise at how quickly the numbers go up.
High protein causes insulin resistance surprisingly. And insulin resistance causes fatigue.
Another food associated with fatigue is high mercury fish. So if tuna is the one you are having, don't have it every week and try to go fresh .
I no longer eat fish, but when I did, I use to boil some frozen cod (put in cold water, bring to boil, when fish floats, it is cooked) , drain and leave in the fridge and then eat a filet cold, straight out if the fridge, covered in lemon juice . With a butter lettuce, it was really nice. Or, as you live in the UK (I presume) , a small sole, cooked in a pan, with just the tiniest amount of butter is delicious and ready in 5 min, no smell, no mess.
Or instead of your omelette, try making your own hummus (a can of drained chickpeas, juice of 1 lemon, a bit of garlic, 1 tbs tahini, olive oil, blend) , eaten with celery sticks, it is a delicious lunch. Don't eat all of it in one day but it keeps in the fridge. Have celery always ready to eat in the fridge (wash, cut into stick and put in a container full of water and keep in water in the fridge, it stays crispy and nice and ready for so many days. ).
You can have very nice salads, without the need to add fish/meat/eggs/or beans.
Try a celery-oranges salad for dinner. Slice as thin as you can manage, squeeze an orange, salt and olive oil, leave aside for 30 min , then mix and add a bit of vinegar. done .
Try to experiment and eat 20 different kind of vegetables every week. It sounds like a lot, but it is only 3/day. When on a diet for a long long time, menus tend to become very repetitive. You end up eating the same meals rotated. Over and over again. It is safe and easy. But when it comes to micronutrients, variety is the key. So one day, cucumber, spring onion and tomatoes salad, next day an artichoke with vinaigrette for lunch (can you tell I am French! I love artichokes!!) and celery and carrots with hummus for dinner, next day green beans, red onion and olives salad and a tiny amount of feta for lunch, a pea soup for dinner and so on....
I hope you will find your energy back quickly.