Good. For the record, as far as I know atmospheric science actually requires a good bit of physics - so if atmospheric science is your dream, then you should make it your goal to become stronger in physics. But you can handle it if you put the time and effort in to practice, seek out help and study! 
No, this is not true. Most biology majors are [gainfully employed straight out of undergrad](https://cew.georgetown.edu/wp-content/uploads/HardTimes2015-Report.pdf), with no graduate degree. (Scroll down towards the bottom for unemployment rates by major. And no, most of them [aren’t in low-skill retail or food service jobs](http://www.nber.org/chapters/c13697.pdf), either.)
Biology majors don’t have to go work in biology. Most of them don’t. [url=https://www.census.gov/dataviz/visualizations/stem/stem-html/]This[/url] visualization from the Census Bureau is pretty great; the majors are on the left side and the careers are on the right. You’ll see that only a very small sliver of biological, environmental, and agricultural sciences majors go into life sciences jobs - or even STEM jobs in general.