weight loss problems

i have put my details in and it says i should eat 1770 calories a day (quite a lot) do i need to eat all these calories? i have 700 cals left to eat tonight.
i work out 3 times a week with walking inbetween. my exercise is very hard. im doing interval training. considering i have done this for 7 and half weeks i expected to lose quite a lot of weight by now but i have only lost 5 pound and gained a size. quite upset as i have tried really hard and considering i need to lose 6st i expected a bit more weight loss and at least a dress size smaller not bigger.

What am i doing wrong? please help!