wow the calories add up fast

Today was the first day I really blew my new eating plan. I did great until my son invited us over for dinner. I don't know how everyone handles it when you are at someone elses house with no choice of the menu. I added up all my calories when I got home and I was shocked. I ate as many calories tonight as I should have had all day. So does anyone have any great ideas? The food was good and I didn't eat huge servings of anything. I should have passed on the salad dressing and the dessert. My daughter in law made my favorite zuccini bars - just for me. So what do you do? I had some. Probably not the smartest decision. Anyway, tomorrow I will be back on track. I never felt out of control but I didn't realize how bad I was eating either. Checking the calories helps because I find my trouble spots and will be better next time. I think next time I will take some of my own veggies and fruit and then I will have better choices.