IP43 hit the nail on the head - yeah, what you nibbled won't likely have a huge effect - BUT it's the mindset that you need to beat into submission
The nibbles might bump you out of ketosis but you will be back in a couple of days if you stay on plan, so your overall losses probably won't be affected. What you need to do is exactly what you did - recognize what went wrong, plan on how you will beat it next time, and get back on the horse!