It doesn't look good, if I'm honest. Without knowing any details, my first thoughts would be that she's either:
- Feeling suffocated by you. Are you texting her more than she texts you? Are you texting her for the sake of it, and getting short answers, but texting back anyway? Give the girl some space and she may start texting you more. If she doesn't, she probably isn't interested.
- Not interested in you. It can be easy to assume that someone likes you, just because you want them to. This is wishful thinking, though, and she may have been replying out of politeness, rather than because she likes you. If she's suddenly stopped, it may be because she doesn't want to lead you on.
- Has other things going on. She's got a life too, you know—it's possible something's come up, and you're not her main priority right now. She may even have lost her phone, or not have it with her.
You don't want this girl to think you're being really possessive, clingy, or overly-attached. There's nothing worse!
If you've been texting for a while, and you genuinely think she liked you, call her up or text to arrange a discussion in person. If she doesn't reply, take the hint. You don't want to embarrass yourself, or cause her any stress.
Don't be angry with her, though. She's either trying to spare your feelings, or she's got a genuine reason for not texting back.
Also, remember that she isn't obliged to reply to any message you send her. It's her choice whether she communicates with you or not, but if you've been pushy or full-on, then the only thing you can do is back off, however hard that may be.