I've had feet probs partly caused by tight calves. So, FWIW, my thoughts:
Firstly, I'm surprised that your physio didn't give you any more advice, if that's all he's prepared to say, then it's not really helping you. I'd see another physio and try to find out what's causing this. If he can "feel where the pain is" then I'm surprised he can't tell you what's causing it.
Secondly, you may possibly have a small tear in the calf itself which is semi-repairing, then re-tearing as you keep exercising, even walking.
Again, you'd need to get a proper diagnosis to establish this and then you'd expect a programme for recovery, which, I suspect, will include rest.
You don't say where you live, but I'm in Hampshire (ie local to the GSR), so I can recommend a good physio, and, should you need it, podiatrist. If so, pm me and I'll let you have the details.
I don't think that it's enough to give up, there are a lot of people on here who have had really bad times, recuperated and gone on with training. I just think that you've got a crup physio who hasn't diagnosed your condition.