Bitcoin adjusts its difficulty every 2,016 blocks (~2 weeks) to keep the average block time at 10 minutes. A positive change means miners are joining the network.
This page tracks the retarget itself, not the absolute difficulty value — that is a dimensionless number in the order of 1014 that cannot be compared to anything on its own. What matters in practice is the percentage change at the next adjustment, the blocks remaining and the time until it happens.
The estimated time left keeps moving, and rightly so: it is derived from the pace of recent blocks, which is itself random. Ten minutes is an average, not a schedule — a single block routinely takes two minutes or half an hour. The closer to the retarget, the fewer blocks feed the average, so the estimate is least stable right before it takes effect.
The link to price is indirect and lagged. When price rises, mining pays even on older hardware, that hardware comes online, and difficulty follows a week or two later. Falling difficulty means the opposite — miners unplugging machines, which historically followed price crashes and country-level crackdowns. Difficulty therefore does not predict price; it confirms it, late.