Quit smoking, Weight gain?

Ive spent the last 7vn months eating healthy ect.. to lose weight and lost 3 stone.But ive quit smoking im on my 6th week and ive been pieling the weight back on, wich im not happy about after all that hard work loseing it :@!. Wich is making me wanna light up again ,wich im not goin to do! but its just worrying me!. Ive put a stone on in 6 wks so im just thinking how much more is gonna pile on in the next few months,considering im only on my 6th week. Im gonna start runing next week about 2 miles a day 3 times a week and goin to eat healthy,Will i lose much weight do you reckon? im 19 11 stone 5 ft 6 and also do you know what weight is healthy for my hight? i seem to be freeking out 2day just panicking about everything lol i dunno if this is just part of quiting. cheers = ]