I think I'm getting fat... :(?

Hola. So last week I was 97 pounds. But then I started eating a lot of junk food and pop . And i mean A LOT. Now , I weigh 101 pounds, and I feel very fat. Well, not fat.. but just bigger than I was last week. I noticed my thighs are a lot thicker, they used to be really thin . My hourglass figure is fading, now I kinda look like a straight line. :/ I'm thinking of going on a diet..just to lose a few pounds.. What do you think? No rude answers please. Thank you .