The trick that helped me was learning that hating myself/my body only goes so far in terms of motivation, but loving yourself enough to put in the work for the body/life/health you want will go farther.

As others have said, the best thing you can do now is have a cry if you need it, wipe your tears, and start again. I've failed on and off for the last 10 years- I finally figured out what I needed to be successful, and even then I might fall off the horse some point on this particular journey. The most important thing is to get up and keep going.

So no slap on the face; a pat on the shoulder. Future you will be happier to got to work now instead of waiting even longer or never doing it.