Thank you very much for the responses.

I am doing my best not to think about this fall but I have had PCS symptoms on and off for the past 6 years. In the past few months, I have had periods feeling mostly normal and periods with quite some symptom flares.
Experiencing any type of fall or head bump therefore makes me quite anxious because then I can directly link my symptom flares to an incident rather than being able to tell myself that they are just symptoms which will eventually go away and which are bothersome but not due to any serious new injury/trauma.

The first few days after the fall I mostly felt normal aside from some headaches. I also had soreness in my upper arms and under my armpits, which I presume is from suddenly contracting those muscles to break the fall and keep me from sliding down the stairs. I have not had any neck pain.

However, since day 4 after the fall, I have started to have much worse trouble with concentration and dizziness (not a spinning vertigo but more of a subtle unsteadiness that feels like it comes from behind my eyes). These are two symptoms which often come and go for me, however it has been quite bad these past few days.

Does it sound like these symptoms could be from the fall?

Does the fall sound like it was enough force to cause a concussion?