Have you thought about what it is about the childcare job that stresses you out? Maybe knowing that would help you work on solving it?

I had a stretch where my job was stressing me out SOOOO much that I was actually getting ill and then having to take about 1 day a week off work (I'm a teacher, but was through a sub agency so I was losing 1/5 of my wage each week as I did not have sick days!) and that was due to both my personal life and being in an episode, but also due to the work stress. When my work stress was alleviated (the headteacher was actually removed) I found it a lot easier to be at work because I actually felt like there was some support there.

With your dream job giving you more hours, are you able to survive off that? I'm going to guess you can't or you would have quit the childcare?

Does the childcare job know you have a second job? If so, why not talk to your boss there about how your dream job is offering you more hours and that you'd realllllly like to have them, but that it would mean having some reduced hours at the childcare job? (Let her know roughly how many hours you want/need to have reduced). It shouldn't hurt to ask her about that, and then you're not even having to talk to her (at least right now!) about the depression and stress.