How do you stop living in the past?

Past therapists never tried to help me with PTSD and I'm currently on a very long waiting list to start with someone new so I have no one to ask.

I (40 F) went through a lot in my past. Family trauma, relationships, a few major one-time incidents so I'm a mixed bag. My current situation is that my health is in decline plus I'm my daughter's (18 F) caregiver for her disabilities so my life is isolated, boring, repetitive, but also stressful. There's no positive future to hope for. With that, I end up constantly ruminating about the past.

I guess I'm just looking for ideas of how to bring myself more present but also not get stuck on today's stressors. A way to quiet my mind. I have ADHD also and find it hard to distract in any way since I seem able to focus on two things at once.