Issues getting enough calories?

I was diagnosed with GD two days ago. I've been tracking my carbs for a couple days, and putting all my food into an app (my fitness pal). And at the end of the each day I ended up being about 500-700 calories short. 
Like today I had:
Oatbran with almonds
Strawberry jam and PB sandwich
Medium Carrot
Taco-chicken, cheese, sour cream, salsa, flour tortilla
Fresh Strawberry & Blueberry & vanilla yogurt smoothie 
And because quitting soda cold turkey sucks, I had 1 can of Coke. 
Before bed I'm going to have a slice of bread with Peanut Butter 
This leaves me about 400 calories short for the day. 
For the sake of my sugar levels, I shouldn't just add 400 calories right before bed, right?