I doubt it's serious. She closed out her match yesterday convincingly (61 in the second set) and it would be unusual if she came down with something serious between then and today. It's probably a case of 24-hour food poisoning or something similar.
You can have reason. It remains inscribed in the next tournaments that it had foreseen to dispute (week 20-26 august), the 25000's of Charleroi and of Prague.
During her semifinal match against Savinykh she called for trainer at 4:3 first set .. it didnt last long, it was for her lower back but right after that she continued playing without any problems and won ( helped with 63536 Leras errors ) She seemed happy and surely not badly injured ..