Maybe its just time to reduce your workload.
I'm 50m now, but I've always bought cars that have depreciated enough for me to be able to afford them, but not enough to keep me under them all the time.
With "normal" cars, this used to be about 100K miles, with a Mercedes it's probably 200K miles. These are rough figures because you never know how the previous owner treated her.......
The tough part is knowing when to let go before she costs you serious money.
There's not many jobs on the car that I actually enjoy, but I get great satisfaction knowing that the job's done properly, and I've saved a fortune.........the kind of money which would have made Mercedes ownership unthinkable if I payed a garage to do it.
There's psycological effects going here as well, at 21, I probably felt just as bad the next morning after as hard day's car-fixing, but I had more important things to think about in those days