to me, it looks like you just don't eat enough, and the food you do eat looks... pretty miserable, and well.. not very balanced.
you've listed:
two buttered toast, breakfast
fried rice, chicken curry and dual and Greek yoghurt for lunch,
piece of breaded fish or scrambled eggs for dinner.
1L water a day.
I'd recommend:
ADDING beans (1/2 tin) OR scrambled eggs to the breakfast toast. every day. That means breakfast comes in around 350 cals, and also means you get protein and carbs for breakfast -- which will keep you feeling fuller for longer. ADD a glass of fruit or vegetable juice, too. Iron (from beans/eggs) is better absorbed when combined with something high in vit C.
midmorning snack: piece of fruit.
lunch: keep the chicken or fish, ADD a massive salad. Be careful with dressings, though. Measure out a tablespoons worth. That's usually a portion of dressing (about 15mls). A tin of soup doesn't sound amazing, but it's quick, cheap, easy to control portion size.
afternoon snack: 1oz of nuts. doesn't matter what nuts -- unless you're allergic, then, obvs: don't! Nuts, in the afternoon, can give you a protein kick, keeps you feeling full, and stops you craving sugar/prevents the mid-afternoon carb slump. There are lists you can find which tell you how many (number) of nuts equals an ounce. Stick to that. Don't just 'grab' a handful, or guess. Actually count them out.
dinner: a sensible, normal portion of real food. Not takeaways, not something out of a box/packet: say, a nice homemade spag bol, a low fat veg curry and plain basmati rice. Portion control is key, for your main meal. And, you get to add loads of healthy, fresh, low cal veg.
Look into just how much food is a portion. Start looking on packets and weighing your food. It's a bit of a faff, in the beginning, but once you realise just how few chips or how much rice, or how little pasta is a 'portion', you gain better control.
snacks: depends how sweet your tooth is. I like jellies. 50 cals a pot. Three choccy digestives, anything that you like, that you can measure out, and control intake of.
hope some of that is useful x