Advice on Coping with a death?

i was out with my husband today on a day trip in the hills with a lot of other people we were all riding on motorbike's a guy hit a barrier and came off he seemed to be all right but the ambulance took over 50 mins to get to him in this time i watched him die it was so sad and i tried to give heart massage but just could not do it everyone tried to do there best but it is so much in my mind i feel so upset as it showed me nobody knows what is round the corner i am now worried about going out again on a bike but i don't want my husband to either any advice