Jaxx01,how horrid for you, I sympathise, because it is never good getting bad news from your dentist. Recently, I found a huge lump on my gum, growing down in between two teeth at the front. I was afraid it was cancer, and was a bit frightened. However when I could not bear the throbbing any more, I did go to the dentist. It turned out to be a hyperplasia,( and not a malignant cancer) caused by a high blood pressure pill called Amlodipine. Removal of the lump required surgery and a bit of jiggery-pokery to make it look as good as new, which it does now. The surgery took an hour, with local anaesthetic,and was uncomfortable but just bearable. I kept my eyes closed tight the whole time and went into what I call "endurance mode" even though there was a ceiling mounted TV with the cricket on. This is too much information, I know, and you are very young to be contemplating extraction but just to reassure you that if the worst happens and dietary changes fail, dentists are very skilled at renewing function.
Btw, my dentist recommends a toothpaste called Parodoxon and a mouthwash called Curasept which does not discolour teeth. Best of luck to you