Im 18 and cant stop going to the dentist

Im 18 and cant stop going to the dentist, I have had 2 root canals (one needed after trauma) done and more fillings than I can count, today my furthest back bottom molar started hurting, but its a dull pain that wont go away, exactly like how it was before I needed the root canals.

I dont know why my dental health is so bad, I brush my teeth twice every day, and at night with fluoride toothpaste, I floss 3-4 times a day, I rinse my mouth after eating basically anything, yet I keep ending back at the dentist

Not only is it worrying, im worried to lose all my teeth and need implants way too soon, its also just embarrassing and ruins my quality of life, I almost always have some sort of teeth pain, I don’t understand why when I seemingly do everything right, I really hope I don’t need another root canal, that would genuinely be awful, 3 root canals at 18…

My teeth all look perfectly normal, but genuinely like 35% of all my teeth had a filling at one point, and my gums also bleed when I brush

I guess my question to the dentists is, what should I do? Is there anything I can do to make my teeth less sensitive? What else can I do to prevent this? What are some things I should do / keep in mind when brushing to improve my dental health?