Congrats on the 9 months of diligence.
Based on 2700 as your maintenance baseline (TDEE)
Day Calories
Monday 2200
Tuesday 2200
Wednesday 2200
Thursday 2200
Friday 2200
Saturday 10000
Sunday 2200
Total 23200
lbs gained 1.23
End Result 172.6
Initial 171.4
(This is from an excel file I custom-use for myself, adjusted on your TDEE, so the bottom segment numbers might seem odd to you)
You gained 1.23lb. The rest is most likely from water retention and excess glycogen, maybe even fibre if you ate a crapload of Protein bars (QuestBars have 17g per bar, if you ate any of those).
You'll be fine, don't overthink it. Use the extra surplus to help yourself in the gym. The energy provided should be a nice small boost. Everyone falls off their horse once in awhile, its not the end of the world. What's important is that you don't have the mentality that because you messed up that day, you'll yolo the rest of the week, and end up in a repeat process over and over.