Get some microplates - 1.25 lb. plates so you can make 2.5 lb. jumps. It'll probably help you when you get to a point like this again.
Could also ratchet up your diet a bit more to ensure you get stronger.
Also, try dextrose pre-workout - might benefit you. It helps me.
But yeah, all else fails, scaling back and ramping back up is the way to go.
Maybe try scaling back to 80% of your current PR, then the next week hit 90%, then try again. That means drop to 120, go up to 135, then try at 150 again. Just a little trick I learned, seems to work well.