Needing motivation too!

I'm guessing your talking about refined sugar. Sugar isn't evil, it's just a carbohydrate, so if you're feeling rubbish afterwards because of guilt then you can stop being guilty and enjoy your sugar. Within calorie limits of course.

If it's the actual sugar that's making you feel bad perhaps try a bit of self psychology. In the past where I've had a behaviour that I wanted to stop I used a kind of aversion therapy. This is a technique I've used with success so might be worth a shot.
The next time you eat sugar (or engage in any behaviour you want to stop) and it makes you feel bad really dwell on that bad feeling. Dive into it and really feel it. Amplify how bad it feels as much as you can, make it worse and worse, kick that feeling up as bad as you can. This begins to forge the neurological pathway in your brain associating the behaviour you want to stop with the bad feeling. The more often you do this and the more intense you can make that bad feeling the more aversion you will begin to feel towards the thing you're trying to stop.

But again, unless there's a reason to stop eating sugar then there's nothing wrong with a little sweetness in your life

Two more suggestions for you to try.

Wean yourself off it. You have 2 sugars in your tea? Try 1. You're going to eat a chocolate bar? Eat half and save the rest for tomorrow. Eat a smaller slice of cake. Sweetener as suggested above can also help.

If you're an all or nothing kinda person then just stop. Be prepared for a pretty crappy week whilst your cravings gnaw at you (and you may experience headaches) but once you're through that then you no longer crave it. You should be able to just enjoy a bar of chocolate once a week as a treat without feeling bad or guilty. This takes self discipline.

Sweet treats are usually my downfall but, in the end, if I wanted to lose the weight I had to stop eating so much sweet stuff.