Troubleshooting Tenor Sax Sound Issue

Hey everyone!
I was looking to get some advice on how to fix/troubleshoot an issue I had pop up with my tenor sax recently.

It was playing absolutely well one day and then the next day, though the notes come out fine (if I play them in a scale-like fashion), when I try to play any of my usual songs the notes sound much more airy and some even "gurgle". It isn't specific so just one note but rather all of them. Additionally it's hard for me to make octave jumps as when I try to jump down an octave the note still gets stuck on the higher octave.

Nothing happened to the sax from when this issue started (I didn't hit it or anything), my embochure is good (I have been playing the sax for a few years now, I may be a bit detrained because there was a big gap in my practice). I even tested the mouthpiece and mouthpiece+neck by itself and they seem fine. Tested different reeds and they're also good.

My sax is still new (only 2 years old), and this is the first time an issue like this has popped up.

I would greatly appreciate any tips on what I could try to troubelshoot (I don't know if its a leak, I am planning on getting a leak light soon to check it out).

I want to try and see if I can fix anything myself, otherwise I may just have to muster up and pay the repair fee :(