I had tendonitis (right tendon only) last year, it still flares up. I did the usual and ignored it and ran on, gritted my teeth regardless, popping brufen. Eventually it got so bad I could not run, then I saw a doc, then I saw a physio. A lot of stretching, strengthening exercises, icing and physio fixed me but it took time. I also found, whilst on a leave period in USA, a very high pressure jet jacuzzi and whilst painful I used the jet to massage my heel and achillies - this has a major beneficial impact - whether it was right to do or not medically, I don't know but it worked for me. If I get lazy ref stretching now, back it comes.
Shortty has got it right but I would add stretching to your list - everyday when you get up and before exercise and after. This is going to be hard to fit in at Para Depot but if you do not do it, you will be fecked in a short space of time. It will get to the stage where you cannot run or load carry so you need to be disciplined and invest time now and continuosly to nurse the injury you are carrying.
IMHO You need to see a physio now for the next 8 days - pay for it if you have to. You definitely need specific stretching exercises for it which a good one will give you.
I also recommend new trainers if yours are old. Get to a specialist running shop and get a gait analysis so they can give you the right trainers with the right support.
I also strongly recommend sorbathene insoles for your boots or at minimum, sorbathane heel raises for running in boots. The physio should be able to advise on this.
Then grit your teeth.
Good luck.