I am sorry to hear you are worried about Smashing. My name is Rebecca. I am a veterinarian and will do my best to help.
If you check her gums, do they look a normal pink color, or do they seem pale?
If she is weak, she may be anemic (and her gums would appear pale if she is anemic), or dehydrated, or she could have a fever, or she could be having failure or disease in her internal organs (kidneys, liver, pancreas, glands).
If she is dehydrated, she would need to get supplemental fluids injected under her skin, or by IV. If she is anemic, she might need a blood transfusion, or medication to build up her blood cells. If I could, I would start with a good physical examination and some basic blood tests to try to find out what is wrong.
Let me know what else I can help with or if you have more questions I can answer.