So I was very surprised to see that I was 300 calories under my recommended calorie intake for the day


Is it okay to be under calories that much? I think because I weigh so much it says I have to eat more. What sort of things are still healthy but help to get your calorie intake up? I can't handle the sugar levels of most fruit so I tend to restrict my fruit intake if I want to stay awake during the day. Plus I'm vegan so no meat or dairy.
This is what I had today:
Breakfast
1 1/2 cups Norganic cornflakes
1/2 cup soymilk (lite with added calcium)
Lunch
2 sushi rolls (1 vegetarian, 1 avocado)
Dinner
Tofu cooked in soy sauce ~100 grams
1 potato
1/2 cup broccoli
Snacks
3 low fat oatmeal cookies (55 calories each)
50 grams mixed raw nuts
150ml apple juice (yet to have)
20 grams vegan dark chocolate