how do you get over bad dreams in the night

last night i woke at 3am after having a nightmare about my mother, in the dream my mother was telling me she hasn't got long left and was very frail looking...i was very frightened and traumatised by the dream as my worst fear is my elderly mum passing on, even though the reality is she is doing well for her age, but just gets tired easily.

it was scary to wake up in the pitch darkness having had a dream like that, plus the fact i live alone too and have no support except my elderly parents who live far away...so there was no one to comfort me.