My obsessions often start before I am fully awake in the morning. I used to engage with them, trying to either solve the "problem" or rationalize it away. I would, of course, get into an anxiety cycle. By the time to get up, I would feel too physically sick to eat breakfast.

Now, as soon as I am aware, I tell my brain: "I hear you. Thanks!" I grab my phone and write down the "problem" into my to-do list. I do this even if I know on a rational level that the "problem" is not real or that I cannot do anything about it. I just tell my brain "There you go, I take your worries seriously, and I will think about this later".

Then, if I am still anxious, a mindfulness exercise. Nothing too complicated, just focusing on the breathing and the body, the empty stomach. I look around the room, and sort of bring into my awareness the fact that I am safe and cozy in my bed.

If the worry keeps coming back, I look at my to do list. "I got you, I will come back to you."

It's not much, but it helps me start the day and get some food. In the evening, I look at this to do item. 90% of time my brain had realized by then that it is nothing to worry about, or that I cannot do anything about it, so I have to let it go. 9% of time it still worries me, but I can't or shoudn't do anything about it, so I put it into my to do list for the next day. 1% of time something needs to be done and I make a rational plan for how to do it.

And that's how I apply "postponing" or "worry time" technique. Hope it helps.