Falling off my bike/ 'Risk Assessment'

I fell off my bike a couple of days ago and cut and bruised myself. What has has me falling off my bike got to do with risk assessment?
I was full of physical confidence  to get over my Ataxia so I wore  tracksuit trousers and sweatshirt and thought 'cycle to park and get strong' None of this physical and mental safetyfirst timidity and so I got on bike. I was stationary at a junction with busy road, waiting for aspace in the traffic near Balcombe Street and fell sideways inexplicably and lay in road for a few seconds, I tried to get up, thinking I haven't hurt myself really and I tried to stand up from road but couldn't get up, my brain sent message to my arms and legs to get up, but they didn't respond a nearby pedestrian ran over to me as a number82 bus avoided me, and helped me to my feet, I felt a little silly and thanked but assured him I was ok, but as I walked on I thought I had better get checked over. I locked my bike up- I wasn't going to cycle again and went to an nearby co-op supermarket and asked to use their first aid kit.  I rolled up my trouser leg to reveal a very bloody knee -the fall had knocked  off a scab from my previous fall. I was cleaned and bandaged up by the bloke in the supermarket. I felt well lookedafter and limped out of the shop, confidence severely dented.
I haven't dared to get on the bike since. That was 3 days ago and have been thinking about how to get confidence  back but without physical risk.
Many achievements come from just going for it and ignoring worry and caution. I have found that when I  list dangers the sensible option seems to be don't try anything. How do you draw the line between a debilitating worry and a genuine risk?
Maybe I can get fit and strong without the 'risk' of cycling. But  a voice in the back of my head cries 'wuss' at me,  but it is always possible to be out of you comfort zone, extend your possiblities without risking fragile flesh on tarmac. Brute reality: flesh is softer than tarmac. I am mostly fine but unpredictably lose all coordination and balance.
so much as though I love hurtling along carefree on a bike, cycling for me is off the menu, but I hope I don't become too timid.
Hmm maybe I should go into risk assessment - "Assessing risk for a big company is easy. Its like falling off your bike ....'