First my question is should i feel guilty for feeling so full?

"The Situation": Today our two offices took a coworker out for lunch for her birthday. I was soo paranoid that i wasnt going to be able to find anything on the menu i could eat or that i would be tempted to eat bad food, that i ran home quick at 11:30 to eat something, anything to fill myself a little before i left so this is what i ate

1 cup arugula salad with:
1tblsp oil and vinegar
1tblsp fetta cheese
5 green olives
1 hard boiled egg

1 italian sausage with VERY few green peppers and onions

I felt pretty satisfied with that, for most people that should be a very satisfying lunch. However we went to lunch at 12:30 and i Knew i had to order something (i didnt want to be questioned) anyways at the restaraunt this is what i got


1 small tuna steak (no roll) with a tablespoon of mayo and a small side salad (that i didnt eat all of) with ranch dressing

now i feel so stuffed and horribly guilty. Is that too much food to eat in such a short time, I gained two pounds when i weighed myself earlier today and i am worried that all the food i just ate is only going to add to it.