So i was playing on multiplayer with the 'All the mods: 3 Lite' modpack which we got from the stickypistons website, we basically used their server trial thing & we were just playing survival. Suddenly a creeper is behind me & it blows me up, i freaked out and started pressing buttons (No idea which ones) and all of a sudden the whole ground, and almost every block had a red number on it. They were all different numbers. It freaked me out, there's a couple pictures below. I tried looking for solutions everywhere but couldn't find anything. I don't know if it's vanilla or modded, the problem has never occurred to me before.
I believe i was in version 1.12 or 1.12.2. I tried looking at all different things in f3 and found absolutely nothing. I went into creative and dug down to find that even the blocks underneath had numbers on them. Thank you in advance for any help.