Ya, it's sneakier than that support cut and paste answer. SURPRISE!
Last week my weekend Quest was $15 for 40 rides. I also had limited boosts, only a few at $6 and most at $2-4 with gaping hours in between availability when it's usually maybe an hour or two about three times a day where there are none. This week my weekend Quest is $45 for 40 rides and $3.50 to $6 boosts as described all week, which is pretty normal and what it was before.
I was talking to a guy in the airport waiting lot the other day and this week he has no Quests and really limited boosts and was asking me about it. Last week when I had crap his were great.
Same market. We're in Tampa. Different bonuses and boosts week to week per driver. The only thing we had in common is we both took a few days off right before the week where our bonuses tanked. At least here with the new Upfront Pricing algorithmic horse-dung pay determinations, it seems if you lower your hours, or at least if you have none for more than a day or two, Uber decides to treat you like a defector for a few days until they see you're going to keep driving.
Can't say it conclusively, or that it applies to your situation, but it's come up a few times in the past few weeks and it seems to be the only common factor. Based on time off or something else, it is definitely no longer a market-wide decision based on expected volume that applies to every driver anymore in my market.
I suppose they could nix all the promotions in a given market if it was slow, but you have Boost+ so I guess you're under the same system we are here. Those aren't usually slower markets.