I think she is just empathic, not draining others. Have her try wearing a black tourmaline point (cleansed and charged properly) with the point facing down over her solar plexus (yes, it will be a long chain/rope--a nice trick for a woman is to wear it tucked under their bra to keep it still). Hemetite works too, just not as well. If she feels better, she is indeed empathic. She should practice grounding, centering, and shielding on a regular basis as well as pulling her own energy closer to her body. Naturally strong empaths tend to extend their auras wider than normal which causes their energy to contact and feel everything within a certain radius very intensely.
Everyone experiences empathic differently. But it can create physical pain and even physical illness (especially vomiting).
Does she commonly avoid eye contact too? That's another sign of a natural yet untrained empath. So is, crossing their arms or legs (or both) when uncomfortable, avoiding touching people or their personal belongings, acting distant toward people they don't know (tend to be loners), etc.