Will one day of overeating make me gain weight?

Today actually started out good-I ran 3.5 miles, ate very well. Until I arrived at my aunts house. My family is CONSTANTLY forcing food on me-b/c they are convinced that I am too thin. Not only do they force it on me, but I feel bad if I don't eat it. So, after already feeling full from my meals today, I arrive at my aunts for an over night stay at 930pm and there is a huge plate prepared for me. I ate as much as I could to be nice. Then to my horror-A HUGE dessert- 2 GIANT chocolate chip cookies with a over sized slab of ice cream. I was pretty much told to eat all of it, and slowly I forced it down. I am also a healthy eater-and a vegetarian so the stuff I ate tonight was not on my diet at all. Needless to say I feel DISGUSTING, and like I have 20lbs of food inside me. I NEVER eat the food /the amount( I also never eat past 7pm) that my aunt fed me tonight. I usually eat 5 small meals a day. Will this one day of overeating at its finest affect my weight? I am concerned because I am a runner and I have a race coming up and I want to be in the best shape. thanks