Most older school staff like me really rate Redoxon Immune Support fizzy multivitamins. And Elderflower syrup for the inevitable lurgies that are constantly going round.
Other than that, kit your desk out with straighteners, have a bath and dry your hair the night before and it's a lot easier to sort out in a couple of minutes in the morning before the kids are onsite. I'd also suggest you stash a blazer and shoes, together with emergency dry shampoo, a brush and some makeup in there.
Get your vitamin D checked - you're indoors pretty much 99% of the day, unless you're stuck on lunch duty, and you're most likely all covered up in summer anyhow, thanks to the Professional Attire rules. If you've got a serious deficiency, you'll need prescription strength supplements and then the daily ones once your levels are back up.
Lay off the biscuits and sweet crap - so no eating the junk the canteen punts out - make a lunch the night before that consists of mostly veggies/salad and a protein source. Stick in a couple of halfway decent (ie, not 99% sugar) cereal/nut bars for when you're too busy or your energy drops. Drinks tons of water, rather than cold coffee.
Make sure you get decent sleep. Same advice as given to kids - no phone or computer for an hour before bed, in bed by ten and a sunrise clock makes a massive difference when you're up at five to sparrowfart every day.
Driving would really help. I can't (medical stuff) and I do wish I could when it takes 10 minutes to get to and from work by car, compared to leaving at pretty much the same time as you do, albeit the main reason I get into school around half an hour early is to guarantee I don't share public transport with the kids, rather than to do my hair. I'd say an intensive course is the way to do - and if you want to pass more quickly, automatics are a viable choice.
I just about manage to stop at the pub on a Friday evening for one drink and then limp the half mile home. To have the potential to run anywhere would be wonderful. Once the driving is sorted, perhaps you could consider shorter gym visits instead of one long run?