Well if you’re stuck with nothing to do, surely doing more vocab won’t overwhelm you, right? It’ll just fill in the gaps, so instead of having nothing to do tomorrow as well, you’ll have い-adjectives to review :)

Also, I’d recommend you don’t review early – there is a logic behind the reviewing intervals and I’m sure you’d get less benefit if you just ignore the “Spaced” part of “Spaced Repetition Software”. If you get a card right only because you saw it earlier on that day, you’re not giving your brain a good enough stretch :P That’s just my feeling though.