Am I going to put on weight if I just ate a tea biscuit, a croissant with cream and 2 cookies? :s?

It's noon and Ive already had a sugar rush :( I have also eaten a bunch of other things that werent too bad. So far I have eaten 1100 calories today. Am I going to put on weight if I just stop there for the day and eat a fruit and some vegetables for dinner? I don't understand this calorie thing. I know that white bread and sugar makes you put on weight, but what if you don't take too many calories? How does that work? Ive also calculated 35g of fat so far. I have been eating very healthy for many days, and Im afraid that my body will store all that food..