I am concerned about 3 possibilities.
One is that you had a posterior vitreous detachment. This is harmless. There is a gel inside of the eye. As you age, the gel breaks up into little pieces. When it does this, you may see lots of flashing lights. Then you will see things floating around. Sometimes you may see a large thing right in front of your vision. Eventually (over weeks) these things calm down.
Second is that you may have experienced an episode of ocular migraine. This starts as flashing and lightning show. This may be accompanied by loss of part of your vision. This may or may not be followed by a headache. The episodes usually last 20-30 minutes before clearing up.
Finally, you may have had an episode of amaurosis. This is the most disturbing. It is like a TIA. There may have been a clot that broke loose and clogged up the circulation to your eye. A lot of times, the clot passes through so the symptoms are only temporary. This is something that needs to be evaluated and treated before a bigger clot makes you lose vision permanently (or an even bigger clot causes you to have a stroke).
I would advise to see an ophthalmologist ASAP.
I hope this helps and thank you.
I'm not sure that the work yesterday would be relevant, except maybe to trigger a migraine episode.
Whether you are seen today or Monday depends on if you are still having symptoms or have had another episode. If everything is back to normal for now, you can wait til Monday. But if you are still symptomatic or have had another episode, you need to be evaluated today.
If it gets worse, you can go to the hospital or call your eye doctor. Otherwise, you still should get it looked at Monday.