Your age will make all the difference to outcome.
If the disc is really herniated, stop the physio until you know what' s going on!! No ifs or buts, just stop. I cannot say enough about some so-called physios that start wrenching away at backs that have a disc with an annular tear. Well, I can, but I would get banned.
This should be taken very seriously. See a neuro/spinal surgeon, and have an MRI.
I have written a fair amount about backs/discs/spines in the last few years. I don't think my opinion has changed much except that I wouldn't use the same traction forces that I launched into while I was learning.
Rest has a lot to do with this problem, and remember, sitting gives the highest core pressures. This is exactly what you want to avoid.
However...there's always a however. If the 'physio' is very highly trained, and has worked alongside surgeons who are monitoring the results of certain manipulations, then there is a chance that they will do you a lot of good. I know when I meet a good one. He asked a lot of questions, and does very little pulling about at the early stages.