What do you do when you start gaining weight again, instead of loosing weight

Depends on timescale and how well I've been respecting my calorie goal:
- if I've been overeating, my first step is finding ways to stick to my calorie goal again
- if I've been following my calorie goal, any changes over less than a month don't warrant any intervention, just patience
- if I've been following my calorie goal, any changes over more than a month: if my routine hasn't changed, I reevaluate my calorie needs and decrease my calorie goal ; if my routine has changed (for example adding strength training to my routine/increased exercise/different eating habits (for example increasing carbs), I don't change anything, I just wait until it's been a month or more on the new routine.