Well done overcoming this hurdle. I used to dread level-ups to an extent as well, mostly because I feel that radicals/kanji are a different and more difficult kind of learning than vocab. The approach I’ve come up with to deal with this is to use the Lesson Filter script to get a fairly consistent mix of vocab and radicals/kanji (between 2:1 and 3:1, currently I’m doing 8 voc, 4 rad/kan), of course with a set number of lessons per day.
This way, my review load is more even, and so is the difficulty level of the lessons/reviews, which has gone a long way towards easing the anxiety over those dry kanji-only days.