Profits have plunged, exasperating investors.Shares of retail chain Dollar General (DG -29.73%) plummeted on Thursday after the company reported financial results for the second quarter of 2024. As of this writing, Dollar General stock was down a hefty 30% and trading below $87 -- it hasn't been this low since late 2017.How bad is it?Investors are likely reacting to Dollar General's lower full-year financial guidance. Management had expected to grow net sales by 6% to 6.7% in 2024 but now it believes it wil ...