It’s good to remind yourself what you like about your job and not just focus on negatives. Maybe social contact is the best thing about your job.
Never skip lunch breaks. I know this is hard as its easy to just sit looking at emails. I always stop and eat and try if possible to get out of the building even if its only for 10 mins.  I am astonished when colleagues sometimes say ‘Oh look at the time. Its 4.15 and I haven’t had lunch’   I find the idea of not eating incomprehensible. I would be in a coma by 2pm
Get up from  the desk every hour and walk about for a few minutes and talk to colleagues if they are open to this/ have a drink(non alcoholic!) and a good stretch
Walk upstairs, several flights is good exercise, raises heart rate and is a good way of combating stress (cheaper than gym too)
If you have your own office  (lucky people) or share it with friendly types who don’t mind a bit of eccentricity you can lie on the floor  for 5 minutes or so. Close your eyes. Good de-stressor. If feeling very stressed some deep slow breathing is helpful. (Tempting as it may be try not to remain lying on the floor all day as this may lead to disciplinary action/ ambulance being called)
Try to see the funny side of things. Humour is a great way of combating stress
Have a good rant to a trusted colleague / friend whenever you are able and return the favour to them- then move on. Try not to carry resentments and try not to take them home.
Don’t send emails when angry. Save in drafts and look again 24 hrs later. Is it really a good idea? I did this recently and when I looked at it the next day decided I had vented enough just by writing it and no longer needed to send it.
I find I need to create a bit of variety in my work by having mini- projects on the go if possible as well as my core tasks.Hope this helps