Create a To-Do List for "Reboot Week" and Establish a Baseline - Get Back into Your Fitness Routine
The penultimate step is to designate a week to get back on your program—we'll call this "Reboot Week"—and create a detailed list of all the things you have to do.
For example, if you're struggling with going back to the gym because you're worried about how weak you'll feel, then your checklist will look like the following:
Monday
Diet: Hit your calorie goals within +/- 3%
Training: Put on workout attire
Get in car
Drive to gym
Do three sets of dumbbell chest press
Do two sets of incline dumbbell chest press
Wednesday
Diet: Hit calorie goals within +/- 3%
Training: Put on workout attire
Get in car
Drive to gym
Do three sets of barbell squats
And so on. Now here's the important part: just get through your list without thinking about outcome whatsoever. It doesn't matter if you've completely lost all of your strength (which you likely didn't) or if you're still up 10lbs on the scale. Focus on getting through your checklist.
Whenever you feel that voice inside of your head reminding you of where you once were, gently refocus back to your checklist and remain in the present.
By the end of the week, you'll have your totals for your major lifts, as well as your weight and waist measurements.