Sympathies, to be honest I think confidence is not a binary thing that you have or don't have, more something which can ebb and flow depending on so many factors, including what else is going on in your life. When I had the worst riding fall of my life about a decade ago, resulting in a broken ankle and months on crutches, I was probably (on the surface at least) one of the people who 'jumped back on and had no nerves' - in fact I rode again far too early and caused myself some extra damage which will probably never fully heal 
. But actually despite this I do think permanent damage has been done to my confidence although I find it's more that I am much less able to cope with stressful circumstances and respond correctly than I was before - it was massively exacerbated when I bought my own mare (fall was off someone's else's horse) - that was a very stressful time anyway as mare was difficult and not really suitable for me in lots of ways and I felt all at sea for a long time and the whole thing was very much tied up in my fears for and about her, would she ever settle, was I doing the right thing by her, was I wasting my time/money/effort etc.
To reassure you though, although I can't really pinpoint a moment when my confidence 'came back' and I would still say I am more cautious or perhaps even sensible (!), conscious that it is possible to break yourself and of my other responsibilities etc. than before, I definitely do now feel relaxed and happy when riding, haven't had a panic or meltdown in years and have even pushed myself competitively a bit in the last few years, so I guess you would say I am confident!
The things that helped, in no particular order were: accepting and admitting that I was anxious, about riding in general and particularly about the new mare and that that was a natural and normal reaction to having had a bad accident (mentally shouting at myself 'WHY ARE YOU SO TENSE! RELAX! YOU'RE USELESS! RELAX!!!' was absolutely not helping 
), using some sports psychology techniques such as visualisation and positive thinking, talking about it to others (but only helpful people, not the kind that would say things like 'oh I never feel nervous' or 'you need to get rid of your mare, she's dangerous'), asking for help from trusted people, including lots of lessons from an understanding instructor (for me this was someone who didn't just sympathise with my nerves but also knew how and when to push me through them, different for different people but I didn't get on with the kind of instructor who said things like 'just do as much as you feel able, it's fine to just groom her/do ground work/ride in walk only,' I needed more of a 'I believe in you, you can do more, I know it's scary but try' type attitude) and also getting instructor who is very confident to ride my mare for me regularly so I could see she was capable of going well, setting small goals (sometimes these were very small, I think the first one was to trot a 20m circle without any panic on my part or mare's!) and pushing myself to achieve them, and creating a 'bank' of positive memories, experiences, photos etc to look back on and see how far we'd come and finally having patience with myself and the mare, occasionally I'd get frustrated that it had been X months and we hadn't done Y or Z yet but instead of getting into a mental spiral of self-criticism and thinking it would never happen I'd try and remember what we had achieved and break down the steps towards future goals...