Start off setting yourself some short term goals and make yourself accountable for reaching those goals
take some pics of yourself and note down your weight, but don’t get drawn into taking pics every week or weighing yourself constantly as it will be 4weeks before you notice any changes in your self (even though they are happening) and the small changes that are happening will seem insignificant and that’s where the negativity sets back in
Also your diet is crucial, more than attending the gym. Diet is everything and 80% of your regime and remember moderation is a word you need to focus on if you get a little slack. A kit Kat once maybe every 2 weeks is not going to kill your diet but 1 everyday might. Work out what calories you need and work on how you will burn the excess energy
from there you will be sweet