Did I Seriously Injure My Shoulder?

Tl;dr: While I was doing incline dumbbell press, I felt my left shoulder slightly pop / shift, and my arm gave out and I dropped the weight awkwardly to the side down to the ground. What did I do?

Yesterday, I did BP, Reverse Grip BP, Close Grip, then some dumbbell work. After work, I decided to go back and do some more chest work. Was doing dumbbell press (warmed up on 35s, started set on 50s) on a slight incline followed by 30# flys. After my second set, I got ballsy and went straight to 60s. About 5 reps in, my arms were at the bottom of my rep in an L shape with the dumbbells facing left to right. As I'm pushing up, I feel something like a dull pop or a shift, and almost immediately, my arm gives out and I drop the weight.

I can still rotate my arm 360° in a windmill movement, lift a light dumbbell out to the side and front to 90°, and still scratch my back and stretch out fine, but there is a feeling almost like I was frogged in the arm.

Any ideas as to what I might have done to my shoulder?

**Edited to remove the "not-so-subtle braging" so I can get actual answers**