More water is an excellent idea, but you might also consider slightly increasing the nicotine. I know that most people gain a good bit of weight after quitting smoking, and it's not just because of eating more, it's also a metabolic change; nicotine is a stimulant, which means it will increase your metabolic rate and also slightly depress hunger.
I've actually lost weight, since now I can sit around and vape, instead of sitting around shoving snacks in my piehole. I was a bit worried that I couldn't maintain the weight loss I enjoyed at first, everything tastes so good to me now, but I just went and weighed myself, and I'm a few lbs less than the last time I checked, about a month ago. Hope it continues; 135 is about my ideal weight, and I'm just a few lbs over that now.
However there is still a third of a red-velvet birthday cake in the fridge...

I may be saying hello to 140 again before that's gone.
Andria