New, and curious about exercise calories

Hello!

I just started here on Thursday so I'm new I started because I was curious just how many calories I'm actually eating every day. I eat pretty darn healthy for the most part, and I work out a lot during the week. I go to the gym three times a week and do a half hour of weight lifting, and then a half hour on an elliptical machine. Also, one night a week I play indoor soccer, and sometimes an ultimate frisbee game. I've been tired a lot this semester (my junior year in college) and I can't tell if it's from what I'm eating or stress (I don't think it's stress honestly). I sleep about 7-8 hours a night, so I don't think it's that.
I've been doing a lot of reading about how many calories I should be taking in every day. I already know I have a high metabolism, so I get hungry just about every few hours. I tend to have many "micro meals" a day instead of 3. My newest question is how to find out if I'm "starving:" myself, by means of just not getting in necessary calories/fat/carbs or if I should be eating more. I'm just trying to find a balance and not sure where to start. Any advice would be greatly appreciated

Here's a breakdown of my typical "workout" day

Breakfast
Sugars - Granulated (sucrose), 0.75 tsp 12 3 0 0
Coffee-Mate - Fat Free French Vanilla Creamer, 0.5 tbsp 13 3 0 0
Coffee - Brewed from grounds, 1 cup (8 fl oz) 2 0 0 0
General Mills - Honeynut Cheerios, 2 cup 293 59 4 8
Milk - Lowfat, 1% milkfat, 0.75 cup 77 9 2 6

Lunch
Fresh - Fuji Apple, Medium, 1 medium 80 22 0 0
Green Giant - Baby Carrots, 2.4 oz(14 carrots) 32 7 0 1
Mustard - Yellow, 0.5 tsp or 1 packet 2 0 0 0
Healthy Ones- 97% Fat Free - Turkey Slices, 5 slice 150 5 5 0
Sara Lee - Heart Healthy 100% Wheat Bread, 2 Slice 240 42 3 10

Dinner
Healthy Choice - Meals - Roast Turkey Breast, 1 meal 200 27 4 14

Snacks
Luna Bar - S'mores, 1 bar 180 27 5 10
Celestial Seasonings - Green Tea , 1 tea bag 0 0 0 0
Starburst - Original Fruit Chews, 2 pieces 40 8 1 0
Frozen yogurts - Chocolate, 1.5 cup 331 56 9 8

Total: 1,652 268 33 57
Your Daily Goal: 2,289 315 76 86
Remaining: 637 47 43 29