Any ideas as to what I’ve done to my knee?

[GoldenSlugPus]

I will be calling my GP in the morning or going to minor injuries.
I’m very overweight, I know this isn’t helpful, and both knees have been on and off sore for the last couple of weeks.

Tonight I was walking downstairs and my left knee as I stepped down made a noise - a click/thud type noise. It felt like it was going to give way and hurt.

I’m now sitting down, it doesn’t really hurt, putting weight on it at all makes it hurt and click inside the knee.
Weirdly I had more limited movement in the joint, but it now more comfortably bends.

I don’t feel I can walk on it.

Do these symptoms sound familiar?

Most likely to be a meniscal tear, but needs a bit more info and an experienced examiner to piece it together for you.

Unlikely to need an xray, but worth seeking proper advice as some rarer things like a quads rupture need treating fairly urgently.

Thank you!
That’s exactly what they think it is.