Category “Q. Catching gum disease”

hello, There is what I think is a crack in my gum. there’s just a dark line traversing my gum vertically. its right between the canine and the tooth behind on the left hand side. my friend seems to thing i may have exercised a poor diet and have put two much pressure on that area consistently whist another has put it down to stress (I do have a stressful job), I dont nkow whats what? I hadn’t noticed it until the other day and as such believe it has only just come to be otherwise I would have noticed it and seeked some form of help before now. have you heard of cracked gums before and what does it mean? is this a sign of gum disease and can I get rid of it, Im wondering whether the gum in that area will grow back or not at all? if you could please give me some information that would be most appreciated thanks a lot.