Yes then no... scared

Kelly • Married since May 2017💜Baby girl born 6/5/19💞TTC since June 2020 for baby two☀️11/20🌈👼 BFP #2 1/5/21🥰

Had a “YES” on a FRER digital around noon today, and tonight it was “NO”, still have lines showing on IC and other tests. Could it just be diluted urine? After a miscarriage this is terrifying to see yes then no.