Keto.. Finding It Hard To Get Bback Into It

I have been trying a keto diet since the start of the month, i did 11 days straight and then had a cheat day (i now know your suppose to only have a cheat meal).

my stats
Training: Wendler 5/3/1
height: 5ft 10
weight: 190lbs
BF%: 20% to 22.5%

my diet hasnt really changed and im following the dave polumbo keto diet

MEAL #1
5 whole Omega-3 Eggs (with 4 additional whites)

MEAL #2
SHAKE: 45g protein with 1 Tablespoon of All Natural PB

MEAL #3
â??Lean Protein Mealâ??
7oz chicken (or Turkey, or tilapia, flounder, or cod) with 1/3-cup RAW almonds, cashews or walnuts

MEAL #4
Repeat MEAL #3

MEAL #5
â??Fatty Protein Mealâ??
7oz Salmon, Swordfish, or 8oz RED MEAT (filet mignon, or top round cut) with a green salad (no tomatoes, carrots, or red peppers) with 1 tablespoon of Olive Oil or Macadamia nut oil and vinegar

MEAL #6 40g protein with 1 tablespoon of All Natural Peanutbutter

if i get hungry through between meals i’ll have a table spoon of peanut butter.

The diet works out at about 2000kcals with less then 20g (i try to keep it between 12g and 16g) carbs.

the first 11 days it was fine, after i hit ketosis 4 days in i tested positive on ketostix and i also had “carb flu” for 5 days.

now i seem to not be able to get back into ketosis, the signs of ketosis arn’t coming back and ketostix are testing as negative (i know they arent 100% reliable). i have also put back on what i had originall lost (although body fat on my tanita scales is now somewhere between 20% and 22.5%).

i’ll admit i thought having a diet coke at cinema on tuesday night was ok but upto research that was a bad idea, something todo with aspartmine.

does anyone have any advice or can point me in the redirection or should i just keep doing what im doing and re-evaluate if not in ketosis by Monday