I am sorry to hear you are worried about your puppy. My name is Rebecca. I am a veterinarian and will do my best to help.
How long have you had her?
If you look at her gums, do they seem pale in color or a normal bright pink?
Is she eating and drinking?
The first thing I would check, if I could, is her blood sugar level. Staring blankly can be a sign of low blood sugar.
How well does she see? Walking along walls might indicate she is blind or not seeing well at all.
You could try giving her a little honey or Karo syrup (corn syrup) when she acts like this. If this is low blood sugar, and she seems better after getting some Karo or honey, I would have her checked for low blood sugar.
Another thing I would check for is a liver condition called a liver shunt. That can make a puppy seem weak, listless, and nonresponsive at times. This condition can be diagnosed by a blood test.
Let me know what other questions you have or how else I can help.