Us Weekly reports that the former Hannah Montana star sent the tweets on September 13 to her millions of online followers.
Cyrus wrote: "Ever feel like you want just... something more? Not sure what exactly. Passion perhaps?"
She added: "Sometimes I feel like I love everyone more than they love me. Hate that feeling.
"Maybe it's not that they love you less. They just love you the most they are capable of loving."
Some fans voiced concern that Cyrus's morose tweets were in regards to her relationship with fiancé Liam Hemsworth.
In response, the 19-year-old singer wrote: "No, there is not trouble in paradise. Just thoughts."
Cyrus and Hemsworth, who have been dating since 2009, recently announced their engagement in May.
She recently revealed that the couple don't have plans to marry any time soon.