I am worried about swollen gums and white goo between a couple of teeth.

Hello, I always floss at least twice a day, sometimes more often, and I don\'t drink soda or eat sweets. I made the mistake of switching to a non-fluoride toothpaste for a couple of weeks, after which I started noticing (only when flossing) a persistent white sticky, gooey stuff surrounding a couple of teeth in a certain area of my mouth. This was occurring by a tooth that simultaneously started feeling slightly loose (not visible to the eye but where I feel it with my tongue). I immediately switched back to a fluoride toothpaste, and now I floss even after snacks (anytime I consume food), giving special attention to this area. I have to floss these particular teeth between the gums over and over again until I no longer see the white stuff, which takes a long time, and then I swish with mouthwash and brush (in circles) with a fluoride toothpaste. I even bought a new soft-bristled toothbrush. Where the white stuff is appearing, I have gum recession on one particular tooth and an exposed nerve, but the rest of my mouth is in good shape. The gums in this area appear a slightly swollen and slightly pulled away from the teeth (because I am getting close to the mirror and really examining them), but they aren\'t bright red, and they don\'t bleed, no matter how much I floss them. They do throb after I\'m done, though. I\'m freaking out because I am a volunteer in a genetic study that periodically tests my DNA for predispositions to various diseases, and I was told that I have ZERO protective genes for periodontitis. I\'m 38 years old, and I\'ve never had a cavity or root canal (seriously), and I don\'t have problems with bad breath. I also had a routine dental cleaning five months ago, and I have another scheduled for next month. Please advise. What is going on?? I don\'t want additional gum recession, and I certainly don\'t want to loose my teeth or need a root canal. I am taking better care of my teeth than most people I know, so I feel like this is unfair, and I don\'t know what else to do.