Overcoming Task Anxiety

I spent all of yesterday at a really great course on Productive Dialogues and influence. It was excellent, but I came home at the end of the day pretty tired.
I saw the pile of emails in my personal/university inbox and my very long task list in my outlook from work and just didn't want to do much.

I had prepared with my materials for two tasks I've been putting off, an expense report and a luggage damage report to the airlines. Often I find that being prepared really helps me get things done, but not this time. I was tired. Instead I hemmed and hawed and did nothing. 

When in that situation I think I'd rather just make a decision to take the evening off of work, give myself permission to just relax, or to get on those tasks.

I arrive at work this morning feeling like I have too many things to do. Notice though that this is a feeling, something I'd blown up and imagined in my head. At that time though it was all too real and felt kind of paralyzing, especially since I was supposed to take my laptop in for service and possible replacement this morning an hour after I arrived.
--edit--
I realized that I failed to mention that having "too many tasks" to do feels like I'm being pulled in many directions at once, it's almost physically painful. Many or all of the tasks seem to be equally pressing and need to be done now. This is about executive function. Some people seem to be able to handle this rather well. Others, not so much. This is made much easier when I do client work, because it's always easy to see what needs to be done next, and I can just prioritize that instead of the myriad of other things pressing for attention. When I'm running my own PhD project supervising two students, and have all these IT issues in the mix, not so much.
--end--

I realized that the amount of data I needed to move and/or back up before taking my laptop in was very significant and would take hours. Often I would just let that kind of change in plans and perceived delay get to me. Inflexibility in thinking or plans is something that helps me choose anxiety and I'd like to work on that. I decided though that clearly the tech would not wait for me, he'd move on to his next thing, especially since when I set the appointment he didn't seem to care when I would come. I started copying and backing up let it run in the background.

What next then? My email was backed up because I of being at a course all day on Wednesday and not being able to deal with that, plus some from Tuesday that came in late after had checked it. I just started working the inbox, doing all the small stuff and putting the bigger stuff into my to-do list. Before I knew it, I had my inboxes cleared out and my to-do list wasn't that much longer for all of the work. My computer was still backing up things so I started in on a writing task, using my 10 minute timer. Thinking "I'll just do it for 10 minutes" is a thing that can really help me get going on tasks and I was able to get some things written.
Soon all my files were backed up and my tasks worked on and my email boxes at zero. Sure I had plenty to do later that day but it was ok.

Lessons learned

Letting things build up can make it seem worse than it really is. When it can't be avoided, I think if I just plan on working on it for 10 minutes will deflate some of the anxiety about that.
When things go wrong, look for something you can do. If I just take some time to think about what I can do instead instead of stressing out about the things I though I was going to do then it turns out to be ok.  I was able to take care of small things that had been needing done on my list. When I went to take the laptop in I packed some paper-based work I could do with me.

Oh and in the end the tech was able to simply swap out my hard drive into a nearly identical computer without any difficulties and no data lost and relatively little time used in the effort.