Take A Deep Breath. Relax.
“The time to relax is when you don’t have time for it.” - Sydney Harris
In the end, though, if you’re feeling overwhelmed with too many words to learn or too many lists, just take a quick step back to breathe and relax. Remember why you’re studying. Is it for fun? Is it for self development? Just remember that by studying Japanese, you’re becoming a smarter person, and you’re becoming better every time you do it. It’s not a race. Do this for your enjoyment (I hope you enjoy learning Japanese!) and not because you think you have to. Make your goal to learn something new every day, not “learn Japanese as fast as possible” (actually, the fastest way to learn Japanese is to learn new things every day, so yeah!).
Take your time, it’s likely you have it. Stop and smell the roses – look up example sentences – enjoy learning interesting little things along the way. You can’t do that by rushing through everything, and you can’t do that unless you study consistently, over a period of time. Remember, this is supposed to be fun, so make sure it’s just that!
If you’re feeling behind on your lists, don’t worry about it. Take this week (or two weeks, or however much time you need) to go back and study old stuff. If you know everything, then that’s great! If you don’t, that’s totally normal, especially at this point. Do what you need to do so you won’t feel overwhelmed when you move on. Remember – just let Anki tell you what to do and make sure you study every day! If you do that, your studying will start compounding and snowballing. Learning will get better every single day.