You may fall behind with your studies or with your credit repayments but hopefully, you won't.

你可能会落后于你的学习，或拖欠你的信贷还款，但希望你不会。

Victor had fallen behind with his mortgage payments after losing his job.

【behind】维克托失业以后就拖欠抵押贷款了。

You may also say it's difficult to keep up with the workload because if I relax just a little and don't do my homework for a few days, I immediately fall behind with my studies.

你可能也会说，很难跟上学习进度，因为如果我稍微放松一下，几天不做作业，我的学习马上就会落后。