Welcome to the club! It's the same for pretty much every poolplayer out there. We're always trying to recapture the magic of that time when we were in dead stroke, and that's why this game is so addicting.
Slumps can come suddenly, but then can end suddenly too, if you don't feed them with negative thoughts. You've already proven to yourself that you can take your game to another level, so just try to stay positive and not get frustrated when things are going poorly and things will turn around eventually. It could just be due to fatigue or anxiety from work, etc., so taking a break and starting over fresh later might be a good a idea as well.
Good luck and here's to higher highs and fewer lows!