Sorry to hear you are feeling unwell.
The old Interferon/Ribavirin was very harsh. You noted it took 9 years to recover from the 2001 treatment and treated again in 2013 with it before the Harvoni treatment in 2017.
While it may be leftover effects from the Interferon, or, less likely, the Harvoni what must be remembered is that Hep C treatment provides 0% protection from all other diseases.
Do you have blood results for full blood count, iron studies, creatinine, urea and electrolytes, vitamin b12, thyroid function, ESR, CRP and HbA1c?
This group of tests looks for a range of other things that make people feel sick.