I went from almost getting to the iron 3 and now I’m literally about to be iron 1 with 0 rr. What could I be doing wrong???

In Act 2, I was a plat 1, almost ranked up to plat 2 and consistently top-3rd fragging and started from silver 2. Since the new act, everyone's been destroying me, and my gunplay feels so... different. It feels like im 500ms behind the game...