Momentous Decision Made

After much stress lately, crying, soul searching and making myself ill, I finally sat down with DH last night and we talked for a LONG time, and have made the momentous decision that I am going to give up work before Erin starts full-time school in September.
I currently work full-time as a legal secretary and the stress is just about killing me, I’m not sleeping properly, I eat junk to comfort myself and am therefore severely obese, and have a very short fuse at home with DH and Erin as a result. I spend far too much time on the pc just to escape as I’m not happy with what is going on around me.
It is something that I never really thought I’d be able to do, but have been thinking about it for a few months now, since Erin starting school became a reality really. What with having to arrange things around school times, holidays etc, I’ve just been sick with worry. My boss also has a young daughter and therefore us both being on holiday during school holidays is impossible. I have been trying to work out before and after school clubs etc as DH works shifts and I therefore cannot rely on him to help on set days each week. I’ve also considered different hours at work but it is not practical and doesn’t solve the holiday issue.
Erin is at nursery three days a week now and goes to my mum’s for two days, and that is hard enough. I feel that I don’t have a proper relationship with her as I’m always trying to get other things done, and she is becoming clingy and tearful whenever I leave her lately which has made me think deeper about things. If I was to carry on as I am she would not know whether she was coming or going.
We have gone through our finances and we can manage on DH’s salary, although obviously we are going to have to make huge changes to the way with live, but currently we end up wasting most of my salary on takeaways, eating out or buying things to cheer ourselves up because we are so tired and stressed anyway.
The plan is to see how it goes for a few months and see if we are doing ok, and if we are struggling or I hate being at home all the time I will look for a part-time job during school hours somewhere local.
I have this inbuilt terror that we are not going to be able to manage money wise, but I have looked into it carefully before making this decision, and it has come to a point where I have realised that I have to put Erin and myself first, and if I don’t give it a try I know I will always wonder what if.
I feel like I missed out on too much with her when she was a baby due to post-natal depression, and I don’t want to waste anymore time. DH has also said he wants his happy wife back.
Sorry this was so long, just needed to get it down in writing to try and clear my head. At the moment I’m veering from terror to elation, worry to excitement, panic to relief.