I lost a lot of weight by diet alone and have kept it off for more than three years - that is harder than losing it in the first place.
Are you mindful of what you drink as well as eat? Some coffees and soft drinks can have a frightening number of calories and/or fat. Most alcohol is a no no, too. Beer, wine and liqueurs will pile on the pounds.
We are too close to Christmas for you to start a proper diet, you won't be able to stick to it over the holiday period and will become discouraged.
You might find Weight Watchers or Slimmers' World helpful - lots of people do reach their target weight on those plans so do some research in to that.
I eat a low calorie, low fat diet but always have three meals a day and I never eat junk. Lots of fresh veg with good quality protein and some fibre every day helped me lose weight and keep it off. It's not easy but then again you wouldn't be able to eat and drink what you wanted if you had gastric surgery.
My breakfast is always porridge with semi skimmed milk. I use the sachets of porridge but it is quick and easy in the microwave but more importantly it is portion controlled.
Lunch is a huge salad (in the old fashioned sense of raw vegetables, not pasta and other fattening foods that come in 'modern' salads) with a spoon of low cal, low fat dressing and a good portion of protein such as chicken breast, salmon fillet, boiled eggs, boiled bacon, left over beef. I do have cheese occasionally - I use the strongest cheddar I can find and grate a small piece - that gives me the flavour and cuts down the calories.
I have the same dinner as everybody else with smaller portions of potatoes, pasta or rice. If the family is having an especially high calorie meal I will have poached eggs on toast, tuna sandwich, soup or something like that.
That is my diet each and every day. No alcohol. No sweets. No snacks. No puddings. No cakes. I limit by bread intake to two slices a week (it works out at two slices every 10 days) and if I have bread for one meal I have no carbs for the other.
I don't eat any 'special diet' food with the exception of my low fat, low calories salad dressing.
I eat everything I want to on two days a year - my birthday in the summer and Christmas day. I also relax my diet when I am on holiday but am still mindful of everything I eat.
I still put on weight very easily and weigh myself a few times a week. Over the years I have probably lost over 30 stone (not in one go!) and am determined to keep the weight off this time because I developed Type 2 diabetes before I lost this weight and have other health complications - and I am getting older, too.
So I reassure you that you can lose weight - if you are determined enough. I wish you well.