The watering can is a tool of daily care, read as nurture given steadily and in small amounts. An empty one may point to feeling you have little left to give.
Where in your waking life have you met something like this lately?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.