it could be the strain i have just had similar stuff with a nothern light after 26 days it was on its 6th node but only 7 iche but it sure made up for that as soon as i went 12/12 it shot up to 18 inches the first 18 days 12/12 so some strains like nl can stay very short if you get the short pheno type ,aurora indica is the same its father is nl their is also other short strain in veg but they grow bigger in 12/12 or later in veg. which node are you on at 5 inches and are the side shoot overtaking the main stem?.the postman. and pics would be a great help as someone says above