What you describe - that feeling when you think of doing those things, my personal experience has me classify it as overthinking becomes getting overwhelmed. And once I'm overwhelmed, I want to escape.
Keeping in mind coping mechanisms aren't one size fits all, the coping mechanism that helped me is to write out the problem step by step. This forces me to think slower, and helps me get out of that recursion of thinking about the same things.
I've also found some success in the age of AI LLMs asking one to break it down as well.
An example would be the dentist. First I need to find one, I need to look at reviews, I need to make sure they accept my insurance, I need to make sure they're reasonably close by. Alright, I compile a list of a few options, now the next part is the hard part: I have to actually call to get scheduled. But once I have it scheduled, my social anxiety is superceded by my desire to just get it over with. Sure I may feel that anxiety once I get close to the appointment, but I can cope with that - the real trick is by breaking down the process I didn't get overwhelmed as quick, and if I did I had notes to come back to.