I've been having this issue too. I switched into accepting that I was FI and not working for money any more on January 1 of this year. My plan has been to continue at the lowest possible part-time level, just to keep current in my profession, and I did cut back on my quantity of work (which had already been part-time). However, I have taken a couple of short contracts that not only pay my annual expenses, they'll put me back into saving mode. I start getting nervous that I'm not making enough, even though I am making around what I always did in a year.
I'm finding it harder than I expected to get into the mental state of accepting that I don't need to earn money. Intellectually I know it to be true, but I don't think my subconscious is there yet. Feeding into it is that my husband worries that I will run out of money and need to work again (despite me explaining the math and the risks, and intellectually he does get it).
Working for money is actually going somewhat badly - the work is still great, but man, where do the find all these dysfunctional managers who thrive on complicating and wrecking any situation that is working well? I am considering stopping the contracts due to this, but it's hard to wrap my brain around. Going full RE is as safe for me as it's every been for any middle-class middle-income middle-aged person, but it just seems so final and drastic. I have decades of conditioning of being a pathologically responsible person to overcome.
I got a good idea from this thread though. Because I keep a larger amount of my stash in cash compared to the average FI person, I hadn't ever considered doing the quarterly or monthly auto-transfer thing. However, as I have more than one bank account and usually keep the functional one pretty empty, I could start doing a monthly auto-deposit of my budgeted amount into that account, and reassure myself that it is enough (or get the very necessary but unlikely wake-up that it is not), and that the rest of the stash doesn't get depleted faster than expected by doing that. In fact, I make myself laugh even considering that, I immediately thought "what a waste to take it out of a higher interest account, I will never spend that much a month". I think I am going to have to see it though to believe it!