congrats on the first race back! i had a feeling you were in closer to 1:57 shape based on that 400 TT you did combined with your somewhat recent 5000 shape.
i would now say you are in closer to 1:55.xx shape actually. what i mean by that is if you were in the perfect race that is paced ideally (like 2012 london olympics 800), which pretty much never happens right, but for training purposes i do think that should be kept in mind.
using 1:55.5, one might expect a fairly ideally paced race to go something like 56.5 - 59.0 or 27.5 - 29.0 - 29.25 - 29.75
from what i can tell we are built pretty similar. prob best at 400-800, but enjoy working out and thus can end up being quite respectable at longer distances as well. in my experience, peaking doesn't come from reducing overall volume and lt work, but instead comes from the energy of the event both in terms of your expectations of it and the vibe at the race.
i'd suggest to keep things going as-is for the most part, let the gravity of the race at nationals be the reason your nervous system is most excited and thus peaks.
sub-50 and sub-1:53 probably won't be happening, but i do think that's closer to your actual ceiling if all the stars in your life aligned.
at your age, just don't get greedy with your workouts! keep a bit in the tank everyday like you've been doing.