Counting Calories Day 1

I am sitting here enjoying my salad and I can't believe that I'm at my limit for what I can eat today already! How do people eat like this?!

First of all I estimated what my intake should be by using spark people. Here's what my ranges are:

Calories: 1200-1550
Carbohydrates: 163-236
Fat: 32-56
Protein: 60-127

I also used weight watchers parameters to make sure those calories are healthy ones:

6 cups of water per day
5 servings of fruits or vegetables
1 serving of milk (or other source of calcium and protein)
daily vitamins

So, with those daily parameters in mind, I attacked my meals today. This is what I had.

Breakfast
1 slice dave's killer bread with 2 Tbsp peanut butter
330 calories, 28 carbs, 19g fat, 9g protein

Lunch
4oz. chicken, 1C brown rice, 1 1/2 C Asian veggie stir fry mix (from Trader Joe's)
1060 calories, 108 carbs, 29g fat, 41g protein

Snack
strawberry cake square, rainbow chip frosting
380 calories, 58 carbs, 8.5g fat, 1g protein

Dinner
1/2 Avocado, chopped lettuce, tomato, yellow pepper, 1Tbsp olive oil, 10 croutons
300 calories, 20 carbs, 27g fat, 5g protein

My totals for the day:
1360 calories, 128 carbs, 56g fat, 46g protein

This feels like a tightrope walk! I figured my small square of cake wouldn't hurt me that bad, and honestly if I hadn't been keeping track I would have had at least 3 squares of cake today. I'm right in line for the calories and fat but I'm lacking protein and carbs. But if I ate something else right now to compensate, I'd probably go over my calories!

I think I understand better now why being a vegetarian wasn't working for me in spite of the improvement in my fruit and veggie intake. If I don't eat enough of all of the nutrients I need I imagine my body will still cling to what it can get to compensate. This isn't going to be easy.