in case you are desperate for a timer and are ok with this method, i use a function in my terminal. i hit F8 to show my drop-down terminal, then type something like:

ctimer 10 get\ drink
ctimer 90

it will show a count-down. if you want to do this, simply copy and paste the following code to the end of hidden .bashrc file in your user (home) folder:

# Custom timer
#  Usage: ctimer [minutes] [short task note]
#  Examples:
#  ctimer 10 get\ drink
#  ctimer 30
counting () {
  for ((i=minutes*60;i>=0;i--)); do
    clear
    echo
    echo -ne "\r  $(date -d"0+$i sec" +%H:%M:%S)"
    echo -ne "  $task "
    sleep 1s
  done
  echo
}

ctimer () {
  minutes="$1"
  task="$2"
  alarm_tone="$HOME/Scripts/alarm.ogg"
  if [ $# -eq 1 ]; then
    counting
    play -q -v 0.60 "$alarm_tone" 2> /dev/null &
    notify-send "Timer finished                          " \
      -i dialog-warning -t 8000
  elif [ $# -eq 2 ]; then
    counting
    play -q -v 0.60 "$alarm_tone" 2> /dev/null &
    notify-send "Do now:  $task                  " \
      -i dialog-warning -t 8000
  elif [ $# -gt 2 ]; then
    echo "Error:  Task has unescaped space"
  fi
}