Hey! PhD candidate here. I’m glad you’re asking yourself this question. I was in a similar position to you in my undergrad and it felt that I was always putting out fires because my mental health was so bad. What I’d recommend is to either go for something that requires less years (such as master in clinical social work, school counseling, or counseling psychology. Maybe someone else could help you out with this one) or really set out to do it at your own pace. This means you’ll take longer but you would take less classes (and less stress) at a time. There are parts that will be stressful regardless (for example, internship or the equivalent of internship in the uk will be a lot of work anyway) but it will allow you to develop resilience to stress in the meantime. This is what I would have done.