i own a garmin instinct solar and i love it - but the screen goes blank

i own a garmin instinct solar and i love it
it is 3  years old
now instead of the battery running down to about 6 days before i recharge the front of the watch just goes blank at about 79% or at  25 days. then i recharge it and it goes for another 2 days or so
can you help me?
is my  watch dying?