Hi Jamie,
Yes, the weight gain. Grumble.
I started late, in a place called Vietnam, dismantling landmines (they call them IEP's these days which is a more accurate description). Still have a piece of the one I was dismantling when I had my first really, really serious smoke.
And I quickly became a 3 pack a day guy. And 20 some years passed. And my clothing got holes burnt in them and my sense of smell was lost and my nighttime cough required nyquill and I spent a lot of money buying cigarettes.
So one day I simply stopped.
And I put on 60 some pounds. Went from a 220, maybe a 240, guy to a 300 guy. That was 30 some years ago and I'm still a 300 guy.
But Its ok. My clothes no longer have holes in them, I can smell things now, I don't cough at night, and I've got some spare money that I once didn't have.
So you may not lose your weight gain. I didn't.
But it has been worth it for me. Hopefully it will be for you also (and who knows, maybe weigh gain can be managed better these days).
Love, Carolina