I’d be chronically constipated if I ate this every day too.
So a typical day for me:
breakfast - porridge oats with honey and two cups of coffee Porridge is not too bad, maybe try less actual oats and replace with some milled linseed, perhaps a couple of dried dates, cranberries, and/or mixed nuts & seeds.
lunch - peanut butter sandwhich with a packet of crisps (I know!) Your lunch is the worst meal of the day, sandwich & crisps are proper gut cloggers, add some salad/veg in to it, ditch the crisps and replace with ‘crudites’ like cucumber & celery, nuts or fruit, opt for berries, pears, apples, or plums rather than bananas or citrus.
dinner - meat and veg (broccoli, carrots, sprouts etc)
carrots are starchy, swap them for green beans, cauliflower, courgette, spinach, roasted peppers
300g magnesium citrate
one ferrous fumerate (every other day) iron supplements are often linked with constipation, make sure you’re taking a gut friendly one, the basic NHS ones are not the best
Tons of sparkling water
One glass of Prune juice
you mention ‘rabbit poo’; small hard stools are a sign of slow gut transit, you can drink as much water as you like but if your food moves through your bowel very slowly all the water is absorbed out and the result is small rocks. You need to encourage peristalsis, to move your food through your gut more efficiently, it’s an old remedy but senna is a gut stimulant, and may help you whilst you wait for the dietary changes to take effect. If you make these changes and it still doesn’t help ask your GP for a food transit test, either a barium meal, or where you swallow a capsule that contains markers that show up on X-rays.