Hi Rosie,
The 1087 calories is based on your goal weight, date, and estimated calorie expenditure. I see that you haven't got a goal weight or date set so if you update those that number will be adjusted to something that should be a lot more realistic!
To set your goal click 'set goal' next to the Your Plan heading on the right.
You can adjust the daily target further with our 'off-set' tool by clicking the Customize Button which appears next to your calorie budget on the Calorie tool page (see below)...
I hope that helps.