Since ETH keeps hitting ATH (well not ATH but almost ATH) there are tons of people making deposits into exchanges and upping the transaction fees. The fees normally are 40-60 Gwei but there were many times in the past 24 hours where they were 400-600 Gwei.
Hence you were making double triple sometimes during the day. Now this is hard for a calculator to estimate because some blocks have more fees than others. You might get lucky and your pool might find a block with 10 ETH fees+ miner reward while on another pool find one that's only 3.5 ETH. Hence why its difficult to estimate your daily profits when the markets are this crazy.
Wait until things settle down... for now just enjoy the profits.