Yes, Hooty, I remember it well! I had so much looked forward to having the cast removed and was appalled at how useless and feeble my wrist and hand felt when it actually happened.
Have you seen a physiotherapist in addition to being given an exercise sheet? I was told it was a month wait to get an appointment so I immediately saw a private physio as I was so concerned about getting full use of my hand back. It was more than worth the cost (£60, about 10 years ago) just to be given some reassuring advice and some supervised exercises to begin with.
I religiously did the exercises for the several weeks until I saw the NHS physio who then introduced me to some more rigorous ones. I thought she was a callous monster and was several times reduced to tears during our sessions - but she knew what she was about! The trick is to stick to the exercise routine. I took two bricks and a can of beans on holiday so I could be sure of having my 'props' at hand!
It will take time but the use will come back. For ages, I was scared on a sort of subconscious level that any undue strain on the wrist would cause it to fracture again. It won't! Honest.
Practise wringing out a wet cloth, typing on a proper keyboard - anything that utilises and flexes the wrist. The activity that took longest to achieve was fastening my own bra.
Mine was a very complex fracture and, a decade on, I have occasional problems straightening my thumb but, other than that, it's fine.