I kind of know the feeling. I've always been someone who is very slim no matter what I eat, but as I've reached a certain age I have noticed this has slowed a little. This has coincided with our long covid lockdown last year, which encouraged couch potato behaviour for extended periods - all I had in my life was netflix and food. So.... fast forward to May 2021 and it's a bit of a squeeze to fit into some of my business clothes. I also generally feel not very attractive.
I know I need to eat healthier and get exercise in more often, but it's so hard to stick to sometimes. What I think is more likely to work for me is if I plan my meals for the week on a Sundays and make sure they are really easy but tasty meals - even something I can cook on Sunday and pop into the freezer for each evening. I find if it's too much work to make my dinner each night, I give in and eat bad food. So the key for me is speed, ease and tastiness. You may even find it useful to look into those delivery nutritious meals.
For exercise, I find there is no point getting into something that is not enjoyable. I simply won't stick with it. I find I enjoy walking so, on my daily strolls I walk just a little faster to get my heart rate up. A podcast or audio book can make it more fun too.
Also, I find drinking water so boring. To avoid drinking too much tea, I sometimes boil the kettle and serve myself just plain hot water. It gives me something warm to hold too. I also try to drink a big glass of water each monring.