Part of what drove me to make the change though was the realization that the gratification was superficial and fleeting, and not at all worth the harm I could see I was either causing or paying for. I think in part this decision was only possible because I do have the means to eat well as a vegan, I'd considered it for almost 5 years (!), and a few key factors in my personal values/philosophy somewhat conveniently fell into place. It's by no means a switch anyone can flick and just become a vegan.
I suppose, like you, I realized that I wasn't particularly happy (quite the opposite at times) and I needed to pursue something more deeply gratifying, or genuinely good for myself or others around me.
It's hard to do. I won't pretend I'm good at it. Take care of yourself though, and don't beat yourself up. Sticking to veganism is legitimately difficult for a lot of people, especially after a lifetime of eating meat. I'd say do what keeps you alive, focus on your health, make the change when you've got the energy and well-being on your side to do it right.
Also when I'm craving meat it tends to go away if I take iron supplements or remember to actually eat enough iron filled vegetables.
I've found I get the same level of gratification from eating really well-seasoned dal (for example) that I used to get from eating meat. As my tastes have adjusted, I don't miss the meat at all. I think what it is though is that I used to season meat heavily, cook it carefully, and it was this delicious, very intentional, and extremely gratifying sensory experience. If I replace that with vegetables, grains, and legumes, it seems to basically do the same thing. I never crave barbacoa beef anymore, but I'll crave chilli or pad Thai (heavily seasoned and savoury or bright, intense flavours) and feel just as great when I eat them.
I also agree that ensuring your nutritional bases are covered goes a long way in reducing cravings (arguably for just about anything).
Veg Thali does it for me. This is my favourite dish(es): https://imgur.com/a/ufsoHD7