Fluer once you give up smoking you will find it easier to gain some weight. Smoking not only suppresses your appetite, but it also speeds up your metabolisim.
I gave up smoking 3yrs ago and I have never felt better. I did gain weight in the begining and after about 12-18mths my body adjusted and I am now a perfect healthy weight. Not to skinny and not to heavy.
You can quit, you can do.
Good luck on your journey. Oh those weight gain drinks are good, keep drinking them..