I think you answered your own question - you learned the hard way that a sudden increse in mileage, (even if you’re fit), can lead to injury.
And changing your form just sounds like a bunch of new problems waiting to happen, I think.
Build slowly.
Also, yeah, strength work - and keep it up during the off season. Strengthen all the muscles around your shin & calf. You can get a thera-band from a medical supply store, (or online, I’m sure), and do resistance work. Wrap it around yer toes and pull toes to nose, and then to the outside & inside - to balance it all. Calf raises, too - to keep it all balanced. It helps.
Sorry you got hurt. Bummer. Ice & anti-inflammatories, for now.