Because if you qualify as a dependent, even if you are not claimed as a dependent, and you are over 16 years old, you do not qualify for the Stimulus Payment.
If you earned more than $4200 during the year, your daughter cannot claim you as a dependent.
How much do you make from working? If it was more than $4200, in 2019, your daughter cannot claim you as a dependent. It doesn't matter how much support, she provided. The income test, alone, disqualifies you.