Ugh help?!

Salina • Lesbian. 18. One son Shaun Brycon ❤️ 1 baby in heaven. Trying for baby #3. Engaged to the love of my life Elizabeth❤️
Me an my fiancé have been trying for little over a month now to get pregnant an I'm suppose to start my period tomorrow according to this app but I've been having like almost all of the early pregnancy symptoms but we took a test an it came up negative. I'm so confused.