Still not runnning

I was making some decent progress until last Sunday when I reinjured my calf. I had got up to 15min on the treadmill a few days before that but after 12 min my calf suddenly went again.
A friend reckons a calf needs 6 weeks to properly heal and be strong enough to run on again.
I clearly need to give it quite a long rest.
In the meantime I am swimming 3x/week and going to the gym.
Its all incredibly frustrating but there dont seeem to be any shortcuts.