I was diagnosed 4 years ago with PBC. Yes, the tiredness is debilitating but I have managed to work full time. I joined the PBC society and it helps knowing there are other people with this condition.
1 tip I have got is to take milkthistle tablets and coenzyme Q10 the first helps cleanse the liver the second helps with energy, there has definitely been an improvement in my test results as my consultant confirmed. This has worked for me and it is worth giving it a try.
Good luck