There could be loads of reasons why she hasn't replied. She could be ill. She could be struggling with work pressures. She could be struggling with mental health pressures. The list is virtually endless.
Not for the first time here, I'll tell you that texting, Facebook messaging, Snapchat messaging, et al are lousy ways of dealing with potentially complex issues.
If you've got the woman's PHONE number, CALL her to talk to her about your problem.