As to your first: if people expect prices to increase tomorrow, they don't save today; they spend today, to lock in value prior to inflation. And even if people actually did as you claim and saved funds today despite their expectations of higher prices tomorrow, guess what: seller's can't eat expectations. They need actual sales. And in your scenario, the people aren't buying.
Well people do both. And different people do different things. I also think a big factor is the amount of inflation. Like the fed targets a 2-3% inflation because that encourages people to spend for exactly the reason you're talking about. Basic monetary theory. But inflation based recessions are a different story and people prepare for the shock. People will hold money because they also expect inflation to reduce and this be a temporary issue. If you expect prices to fall back down, then you should save instead of spending now.
As to your first: if people expect prices to increase tomorrow, they don't save today; they spend today, to lock in value prior to inflation. And even if people actually did as you claim and saved funds today despite their expectations of higher prices tomorrow, guess what: seller's can't eat expectations. They need actual sales. And in your scenario, the people aren't buying.