Like you say hon, one day at a time.
It was bound to be stressful the first night and being sleep deprived and agitated never makes stuff easier does it? :0) So first hurdle over and you’re still at it, inspite of feeling like you want to rip it off. Well done!!
Your doctor is very wise, try to reach out for help when you feel vulnerable, she sounds like a rock *thumbs up and the group here and on FB that JacQ is involved in are excellent support too.
All you can do as you said already is take one day at a time, overnight changes are over rated, stuff you have to work at gives you a better sense of achievement. It’s all about baby steps.
Believe me you can do this, and in moments of vulnerability there’s loads of support here.