I think you are restricting too much, I ran your TDEE which I've attached, you need to be having about 500 calories less than maintenance a day to lose 1lb a week so should be eating between 1400 and 1500 calories.
Your current diet is quite heavy in fruit which will be spiking your sugar levels too which won't help. It's also low in protein and fat, you need fat and both protein and fat will help you feel full.
You must be feeling hungry too and you're still recovering from an illness so your body needs food to fuel it.
Your food diary with some suggestions:
7am: Coffee with small amount of semi skimmed milk
11am: Skyr yoghurt, apple - try switching the apple for berries, nuts or seeds in the yoghurt.
1pm: Fruit and veg smoothie - steamed veg with a knob of real butter and some protein, or soup would still be low cal but less sugar.
4pm: Either smoked salmon or chicken breast with two thirds of plate steamed veg or salad (w/o dressing) - you need some fat - avocado, olive oil, nut butters.
7pm Fruit - switch to veg or dairy snack
Throughout the day I drink either black, green or herbal tea and if hungry snack on celery sticks, apples or carrots.
Healthy low calories, filling snacks:
- veg
- boiled egg
- beef jerky
- nuts (30g serving)
- seeds
- cheese string/babybel