Horrible tooth pain!

Anyone who knows anything about teeth help! For the past little bit the gums between my back 2 molars have been irritating. I’ve been brushing my teeth regularly, and always have, plus I’ve been flossing but my gums seem very red and have been bleeding easily within the past day or two. The only thing I can narrow it to is when I had popcorn a little bit ago and struggled with a piece that got stuck. I’ve provided some pictures of the gums. I have soft teeth with many deep ‘craters’ in them so the dentists have put some sort of gel caps in them, but my past dentist forgot and I done how ended up with 8 cavities (I’ve only ever had one in my life and keep great hygiene) and every since then my teeth have been 5x more sensitive to things. Please help me!