i worry about my mum, even though my mum is alright

i'm very close to my mum and i think about my mum constantly, but my mum tells me i worry unecessarily, because she's doing alright for her age......my mothers elderly now, but i still worry.....is there a way i can stop all the worry?

i think it's i'm scared of my mum leaving me, because i don't think i could cope......my mum lives far from me now, i live alone in a little 3rd floor flat...we speak every day on the phone 4 times a day.

any thoughts on this?