I struggle with this too quite a bit.
My daughter is also the same, she is autistic. I’ve never been diagnosed with anything, but going through the process with her did make me wonder about myself.
If I’ve got an appointment, or somewhere to be after work I struggle to focus at work. On a weekend, if I’ve got something in the evening, I’ll be stuck all day - it’s not an anxiety thing I don’t think, it’s not stuff I’m worried about. It might be a night out. I’ll spend all day doom scrolling, planning what I’m doing to my hair, make up, outfit, etc, and then procrastinate so long about actually doing it, that it’s too late to do any of the things I’ve planned and I often end up late.
DD finds it very difficult to plan more than 1 thing a day - for example, I remember in the summer, she had a work shift at 6pm, all her mates went to the beach for the afternoon, but she couldn’t entertain the idea of going to the beach and going to work later. She spent all day dressed in her work uniform sat on her bed, checking the alarm she’d set to remind her to go to work hadn’t magically turned itself off. I’d offered to pick her up from the beach and then take her to work so she didn’t have to worry about getting the bus or being late but she wouldn’t have it.
I’ve no idea how to fix it. A visual time table helped my daughter - she’s got a white board with everything on - so what time to get up, what time to get in the shower, what time to leave the house, how long she can spend somewhere before she has to catch the bus home, etc. It helped having written down so she could visualise each step.
I didn’t find it helpful though, I know what time I’ve got to get in the shower, but still fanny about.