Do classes instead of going in the gym. Get a personal trainer. Just use them once a month to give you a routine to follow then they can adjust it for your strengthening body each month. Go to the gym when you know the PT is there, they cannot help giving a bit of guidance if they see you there! (Most of them anyway)
You don’t have to eat no added sugar things, but buy natural full fat yoghurt and add fruit and granola to it or a little bit of honey (honey not only reduces the risk of cardiovascular disorders, it also does not increase the body weight.) Full fat foods are better for you that low fat just eat less. I eat less calories during the week and have slightly more at the weekend so it feels like I’m having a normal weekend. Kind of like the 5:2 diet but the other way round and having way more than 500 two days a week!
First I would keep an honest diary of EVERYTHING you eat in a normal week, add up the calories you have consumed and then work out what you can cut out of your diet. Cut the calories by a quarter. Do keep a daily treat, whatever your go to treat is and have a small one at the end of the day.
Find a friend/s and do it together, so much easier when you’ve got some motivation on days you want to give up. Walk more. Get a fit bit type thing. Have a goal. I walk 16,000 steps a day, it’s so rewarding to actually get there, even if I have to walk round the block in the evenings to finish. I started off at 6,000 and moved it up monthly at first then when the weight loss stops.
Don’t weigh, measure! Do 10 measurements in cams, bust, under bust, waist, hips, thighs, calf, upper arm. Measure each week, add up all 10 numbers, you’ll be surprised at how quickly th numbers go down.
Good luck. It’s tough, you’ll have bad days but get over it, move on, start again as soon as possible.