answering yes means you won't get it.  the tax law is not whether you are actaually claimed as a dependent but could someonre claim you

either as a qualifying child or relative

 taxpayer could claim you as a qualifying child if all these tests are met

•  you have the same principal abode as taxpayer for more than ½ the tax year.  Temporary absences like for school are ignored
• If not a full-time student, under 19 at the end of the tax year.  If a full-time student under 24 at end of tax year.  
• you haven't provided over ½ yourown support
• no joint return unless no taxliability but merely filing joint to facilitate refund of taxes withheld or estimates paid

or as a qualifying relative if all these test are met

• meets relationship test
• your gross income for 2019 less than $4,200
• taxpayer provided over ½ your support
• you aren't a qualifying child of another taxpayer

if you are neither you need to amend your return but no guarantee the IRS will process it so you get the payment

however, the actual payment due you will be determined based on your 2020 return,   this is merely an advance. if you are owed,  then the credit will reduce the balance due or increase your refund.