You are frustrated because your girlfriend is not texting back to you. Sometimes you might overwhelmed with emotions. Probably you want to know why she is not texting back you? Does she not liking you currently? But in this regard you can trust me, if you can not control your emotions, you will be deeply depressed.
So without being frustrated, you can follow the advice below :
1. Think your girlfriend's phone is not near to her.2. He is probably busy with a job for which she can not answering you.
3. You would not think of anything unnecessarily about her.
4. Stop texting her for a while.
5. Do not post anything about her in the social media.
6. Wait at least 24 hours for her answer and do not tell anyone about it.
7. Keep yourself busy with other activities or gossip with friends who are around you.
8. Watch a good movie or go around where you get pleasure.
Hopefully, in the meantime you will get her answer. Be well, be happy.