This research by the Institute for Fiscal Studies (IFS), commissioned by the Department for Education, examines the financial benefit associated with different degree classifications.
It contains many findings, including:
"The penalty for getting a lower second (2.2) as opposed to a 2.1 is 7% lower earnings for women and 11% lower earnings for men."
The impact is more pronounced at some of the most selective universities:
"Controlling for observable characteristics, both men and women who obtain a 2.2 from the most selective universities (Oxford, Cambridge, Imperial College London and the London School of Economics) earn 20% less on average at age 30 than those who achieve a 2.1..."
Would you want to be earning that much less? No. Would it be a complete disaster? No.
If you wanted to stay at university (which sounds unlikely, to be fair!) then gaining entry to post-graduate courses would be harder with a 2:2 than a 2:1. Not impossible, but harder.
Note that if you genuinely "don’t really care about how well I do anymore", then a 2:2 might be more likely than you think, given how important motivation is.
Is there a Student Support team (or similar) at your university which can help with your depression?