When I start feeling like your last couple of sentences I break my work up into a list of smaller easier tasks, do a couple then go and take a break for 30 min-

When I start feeling like your last couple of sentences I break my work up into a list of smaller easier tasks, do a couple then go and take a break for 30 min-a few hours. Go for a walk outside, have a shower, drink coffee at a cafe, have a nap, etc. anything that is away from my phone and computers. That usually calms me down enough to work more.