Buffer Good Feelings

I have written my very first book over the past several months, after struggling accommodating discomfort for years.
Thanks to my work here I finally got a hold on honoring my writing schedule, allowing myself to be dissatisfied when my writing did not meet my expectations and complete an entire book.
Two days ago I finally submitted it to a contest and felt very proud of myself.
With the contest schedule, I am not expected to hear from them at least until August so I feel I am moving on now to my next book project.
For some reason I started overeating the past two days and I try to understand why my brain will do that if I feel so accomplished.

Food used to be my go-to when I felt depressed, miserable and disempowered. I now feel capable, proud, and worthy.

When I did my thought download I think I found a thought that sounded like: ‘After all this time and all the struggle, I deserve a reward.’

I know Brooke says we use food to buffer negative emotions but I feel positive emotions about my writing capability that I’ve never felt before. Why would I want to buffer them?