Hi Knackeredmum,
I really do understand why you feel the way you do. i'm not a medic (I'm in the accountancy profession) and had my first DC 5 years ago. Since then I've worked full-time, doing long and stressful hours, with a long and stressful commute, and it was knackering. I wasn't even in a job I loved - I was just doing it for the money. When DS2 came along, our childcare costs were E2,300 per month, which wiped out 2/3 of my salary (and I do consider this a cost to come out of my salary, not a joint pot). DH wasn't earning much so the bulk of our income came from me. Meanwhile all my colleagues and friends in similar-paid jobs to me, who didn't have children, were flying up the career ladders, moving into massive, beautiful houses, and me and DH were barely scraping by and getting ourselves into a worrying amount of debt. It was really tough, but I stuck with it a) because I had to for financial reasons (that 1/3 of my salary that didn't go on childcare made a massive difference to our income) and b) because I was concentrating on the long term.
I'm not quite there yet, but two things happened 6 months ago that suddenly made life a whole lot easier - my commitment to my work paid off, and I got promoted. At about the same time, DS1 started school. Bingo - childcare costs almost halved, salary went up 25%. Suddenly, we're starting to see light at the end of the tunnel, and you will too. Admittedly we're now using the additional money to pay off debts, but once DS2 starts school, it'll get even easier again.
Stick with it, it's tough now, but it won't be like this forever. And your DCs will grow up and be very proud of their doctor mummy 