Hay bales at Burleigh Sands

It hasn't been a good day. All was well in the morning except that I felt gloomy.  My knee was sore and I felt I was imprisoned by my inability to walk.  Chopped down the last of the shrub roses except for two enormous ones.  They will have to wait until I get all of the present lot to the recycling.   Took myself off to Loch Leven's Larder where I bought cake, strawberries, chocolate, some sinful bread sticks and a couple of Cook vegetarian meals then went off to Burleigh Sands. Perhaps because I was gloomy and there was no sun I walked off towards Burleigh Castle. Didn't go right up to it but by the time I got back to the car I'd walked about a mile.  All of which was good but didn't cheer me.  On the way home I stopped at M&S Food Hall. Bought greengages, nectarines, ratatouille, seeded rolls and a bottle of Rioja. Another mix of good and bad.  Got in the car and drove off turning towards the exit after a few yards.  Another car had moved out of its space so I braked but my car kept moving. and we hit.  The bang was really loud and I was expecting a lot of damage but once we got parked out of the way it wasn''t too awful. My car had no damage except some paint scratches.  The other car had a little dent and scratches.
The woman driver was very nice and kind and we exchanged all the relevant information.  I felt very jangled however.  Was there something wrong with my brakes ?  Had I hit the accelerator instead ?  I had no idea. And being old doesn't help. You start wondering if you are past it. Sat for a while then moved a few feet and hit the brakes.  They engaged.  Drove home very slowly braking at regular intervals. They were working but I'll have to get Alan to check the car over on Monday.  Phoned the insurance who were so busy they are phoning me back tomorrow.  The extra is me photographing the car I ran into.  Impressive reflections but don't I wish it had never happened.