same thing happened to me

i was at 22s bankroll up to 60 buyins (starting from 15), then went on a streak of -35 buyins, moved down to the 11s, realized how easy the 11s were for like 2 weeks, move back up to the 20s and so far i've been basically break even

but i don't think i'd ever go back to the 11s unless i absolutely had to