I am anemic from hep c tx. shortness of breath, cold extremities. is this serious?

It can be: Great advances have been made in the treatment of hepatitis c. Not so very long ago it was a life-long disease and now we can cure some folks. Patients being treated for hepatitis C can have a number of reactions to the medications and should be regularly seeing their doctors for close follow-up. If you are anemic, then your doc should be treating you for that before it becomes serious.

Yes: This could be a sign if severe anemia or some other complication. You should notify your treating physician immediately.