Well, you’re in a tough position — along with many other seniors. Likely they reviewed your daughter’s 2018 return, and cross checked your SS number and will not send you a stimulus check.
IF they file 2019 and do NOT include you as a dependent, you can file your own return for 2020 next April (even if not required to do so based on income) and ask for a credit to any taxes you might owe that year. And if you don’t owe taxes they hopefully will send you the money
!It’s worth a try — but they can’t declare you as a dependent in 2019 –and it will take a while to get the money, if ever.