Terrible pain with shin splints - but you know that now
all the above advice is excellent .. but whilst you are waiting and healing do analyze how you walk or you may get them again.
Try this - stand relaxed and straight with your arms down by your sides and focus your mind on the front of your legs from the waist to the toes .. now .. turn your elbows out a little and lean forward slightly from the waist, only the waist - you will feel all the tendons and muscles and ligaments at the front, all the way down, go into tension .. and this will lead to problems when walking - so, you have to walk upright and relaxed, as if your backpack weighs nothing, don't lean forward when wearing it, stand straight and sort of lead with your hips - and if you cannot do that then your pack is either not giving the main weight to your hips (put on wrongly) or it is too heavy .. so go through your stuff and be brutal - get rid of all you "may" need and keep only what you "do" need.
Roman legions marched long distances day after day carrying heavy loads - but their steps were really short, about half the length that we tend to walk, and with higher raised knees too, perfect for rough terrain - so (as mentioned above) shorten your stride - but drastically. At first it will feel quite weird but after a while will seem normal and will eat up the miles with less fatigue.
Same on ascents and descents .. take it easy, take it easy, keep the step length short ....
So, you have the time over the next couple of days to look at all of this, practise it ... and when you are healed, well, Buen Camino!!!!