I’ve definitely been there before… I always just try to get what I can done and not worry too much if I have weeks where I’m not getting an optimal amount of work done. Sometimes I’m busy or stressed or depressed and it’s hard to study, so I just try to make at least a little bit of progress and tell myself that it’ll get better if I just keep going and get through the tough period. And so far it always has gotten better! As long as you’re not burning yourself out by trying to push yourself way too hard, I think you’ll get your studying mojo back eventually!
If you’re really having a tough time, I recommend scaling back a bit and just going into maintenance mode, so that you don’t totally burn out, but try your hardest not to drop it completely.
I really recommend these two userscripts for helping you differentiate similar kanji:
待 and 持 caused me a bit of trouble at first, too. The trick for me was learning to focus on the left radical, which is the semantic component for these. For 持 in particular, the finger radical is a great help for remembering that it means hold! And the loiter radical in 待 makes sense for “wait”!
The phonetic component 寺 is a bit less helpful for this set, because the じ only works for 持, but learning it did end up helping me out a lot when I encountered 峙 (non-WK kanji meaning “tower, soar”) in the word 対峙 (confrontation; standing facing each other). And hey, mountain is a pretty fun component! I can work with that in my memory (and in fact, two mountains standing facing each other is a valid use of 対峙).
My recommendation when you find yourself confusing two kanji is to look at them side by side (the niai script is fantastic for this, especially since you can add your own kanji to it) and identify the differences. Then learn to look for that difference when you see those kanji, and find some way to center that difference in your mnemonic for that item, so you’ll look at 持 and automatically go “Oh! Fingers! It must be hold!”. Most kanji kind of follow a sort of formula in terms of how the components are put together, and you’ll get a feel for that over time, and will learn what information to focus on when looking at a kanji that’ll let you quickly and easily identify it.
I often find that the ones that have a very straightforward phonetic and semantic component are the easiest for me, and the ones that sort of break the rules trip me up. Thankfully, in this case knowing a lot of kanji already can actually be a big help for learning new ones outside of WK’s system. I recently encountered 嫉 in the word 嫉妬 (“jealous, envy”), and I was like "hang on, doesn’t that have a 疾 in there? And sure enough, 疾 is the phonetic component, and 嫉 has the exact same reading!
So instead of being annoyances, these component differences can actually be really, really nifty to help you memorize new kanji quickly and retain the information over time. But yeah, sometimes you do have to take the extra time to examine something a little closer 
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