I'm 33 and just let week had the rude awakening that I now need to warm up to things. Attempted a 3 day 60km walk with lots of elevation changes, on the second

I'm 33 and just let week had the rude awakening that I now need to warm up to things. Attempted a 3 day 60km walk with lots of elevation changes, on the second day my ITB became so inflamed I couldn't bend my knee, and had to abort the walk. Prior to this I've done up to 30km days no sweat (carrying up 20kgs). So I'm feeling pretty depressed. It's not helped that there's so much conflicting advice when it come to physio.