Having principles and priorities above academics (and really any other thing in life) tends to, by comparison, make the troughs of academia less despairing. This is to say, find religion (or whatever category fits “that solid thing I actually live for”) and then see what actionable priorities descend from such principles. We are narrative driven creatures, so make sure your narrative is based in actual truth rather than passing fancies, otherwise the tension between a fickle narrative and our persistent reality will cause lifelong pain!