If you can find the energy I personally find doing projects with my hands helps a lot, (sewing, crochet, painting) listening to an audiobook, going to the park if you feel comfortable to stuff like that, being left alone to your mind right now would definitely be extremely hard
For me, if I catch myself starting down the path of just ruminating on thoughts, I try and ground myself in the current moment with something completely unrelated. If I am driving, I will focus on the wheels and design of wheels on other cars and the patterns they make when they spin. If I am indoors, I will find some object and focus on describing all the details of that object to myself in my mind. It helps keep my mind from having the bandwidth to still sit there and think about whatever intrusive thought was coming in
This is a hard question to ask- We don't want to avoid and we want to be mindful if we are doing that and at the same time I, personally find that the busier I am, the less I pay attention to OCD stuff- which is something I hear many people I would with also say.
Definitely respect your energy needs though and don’t throw yourself into a heap of work though right?
I found that by using an attention control training exercise - as a part of metacognitive therapy, I think produced by Brian Wells - I am sometimes better able to attend to the concrete matter at hand & not be as subject to derailment by the intrusive thoughts. Situationally/contextually, it also seems to help if the project activity is one that other people are right near by waiting on me for. When alone, it is harder not to let myself be 'carried off.'