My understanding is that most people that increase their earnings significantly over time do so by moving employers and pushing up their salary with each move. If you feel your employer is not valuing you appropriately or you are unhappy in your role then the right thing to do is to move.
I understand that you are not in the right headspace to do that right now. The right time for that was probably quite some time ago. Now you might need some time to recover.
I remember hearing that the worst jobs for stress are when you have high levels of responsibility but low levels of control. For example the CEO has huge responsibility but he can say "Let's push that project back 3 months/let's change direction on this project". People without much control just get the stress of unrealistic deadlines/inefficient procedures and no power to change it.
I'm sure you are a capable lawyer but when you say the thought that if you weren't good lawyer makes you want to crawl into a hole and die think about how you would feel if your loved one said that.
I obviously don't know what your partner does but let's imagine he is an accountant. Imagine he makes a few errors at work and fails an exam. (I'm not saying you have made any errors of failed at anything!) Imagine he then says "If I'm not a good accountant I want to crawl into a hole and die". Would you not want to say "Err hello - it's your wife here - you know the person you just promised to spend your life with, look after in sickness and in health - if accountancy isnt working out just get another job!" is there not more to life than whether you are a good accountant?
My husband's a teacher. If he's unhappy at work I want him to get a different job,or if he needs to go off sick to do that, or if he needs to quit to do that. I couldn't give a shit if he's a teacher or not I just want him to be happy and to have a happy home life. If you Imagine a person's life as a pie chart your job is just a slither of who you are. And that slither can be swapped out for another job.
I ran the London Marathon once - quite some time ago in 2007. It was a very hot day and I remember thinking all the banners about keeping going, digging deep etc etc were quite irresponsible in a funny way. 73 runners were admitted to hospital that day. If you're doing something you dreamed of and you are very determined rethinking and giving yourself a break is the hardest thing but sometimes it's the right thing.