Many people find themselves in this situation ... overwhelmed and unsure about how to dig out from under the pile! I could talk all day about good time management practices but when you are in this position you just need some help.
"Time is what we want most, but what we spend worst." William Penn
Make something happen. Inertia is addictive, and the more you become paralyzed by your situation the worse it gets. So pick something that is important and just get it done! Focus entirely on getting that one thing done and ignore the other things on your plate.
Once you have one thing off your plate ... remind yourself that you did it! You had a success. Do NOT get overwhelmed again ... pick another thing. and get that done.
Choosing the things to get done can also be paralyzing ... so don't overthink it. Remember you were getting nothing done before, so this is significant progress.
Complex tasks can be tiring, and completing them one after the other can be draining. Mix things up a bit by adding in smaller (still important) tasks in between the larger ones.
Completing work gives a sense of accomplishment, and provides a little relief to that "overwhelmed" feeling. However, it is only by taking control of your day that you will feel in control, and relieve that stress.
"Procrastination is the foundation of all disasters." Pandora Poikilos
So ... the long term solution is to get organised!
Create a To Do List (or several To Do lists ... all the tasks you NEED to do.
Prioritise your work ... what is important and what is urgent!
Organise your calendar so that you have time set aside for the work to be done. Create meetings with yourself so you won't be interrupted.
Delegate what you can ... if possible.
Ignore what you can ... not everything is important.
Be very focused on getting stuff done ... rather than worrying about how you will get it ALL done..
Use the triage method of organising your work, just like the hospital. The most urgent (and important) items get done first.
Get help! Whether it could be advice and guidance from your management, ideas and tips from your colleagues, or training on time management from wherever you can get it!
Life is too short to be living under such stress. If you apply your skills in an organised manner you may well surprise yourself at how much you can achieve AND how good you feel about those achievements.
"A good plan, violently executed now, is better than a perfect plan next week." George Patton
Good time management practices could probably reduce workplace stress significantly!