When I feel like my reviews seem like a lot, I’ll plan to only do a few. If I’m tired, or I’m not concentrating, I’ll stop there, and at least I’ve done some, which is better than none, and I’ll come back to do more later. But sometimes it’s just my executive dysfunction making it seem like a lot and making it difficult to start, and once I have, I get into the swing of it and I’ll get a good chunk of them done - depending how many I have ready, I may get through a quarter, or half, or even all of them. Sometimes when I’ve got a big pile waiting for me, I’ll wait until ~10 min before the hour to further separate the ones I complete so I don’t get them all (at least, that are at the same SRS level) all at once again
If you’re getting a lot wrong and it’s adding to your stress… I know it’s hard (I’ve always been a perfectionist afraid of failure so this is something that I’m working on too), but don’t let it get to you. If you’re getting something wrong, it’s because it’s not sticking and you need a little more help learning it, and that’s what the SRS is designed to do. Maybe you just need the bit of extra repetition, maybe you need to figure out your own mnemonic or other method to remember it (or even fall back on rote memorization if that’s what it takes for this item); it’ll take some time, but you’ll find that you start getting it right more and more often, and eventually you’ll see it and just immediately know what it is
If your current rate is overwhelming for you, then stop doing lessons at all. If you feel you can do them, then great! Do a batch or two! But if not, they’ll be there when you are ready. Find some way to whittle away at your reviews - whether it’s five minutes a few times a day that you decide you’ll sit down and do as many as you can, or doing 5 reviews every hour, or whatever it is that works for you - and eventually you’ll be getting fewer at a time because there’s more time before you get the next one. The only one who can set your pace is you