Any slowness should be gone by now, I haven't seen the JSON thing happen to me yet, but I'll look into it. Next time it happens to you can you DM me a screenshot?
We've been targeted too by what's probably a couple of script kiddies trying to brute force their way into our server. Not exactly a DDOS but a similar effect. Just had to remodulate the shields a few times.
Stories like this make me very happy to hear. When I heard the /r/StarTrek and Daystrom mods talking about joining Lemmy I'd thought bringing their reputation for positivity and tolerance to a Trek-themed instance could provide a familiar and comfortable jumping-off point for users unsure about the broader Fediverse.
Should be fixed now. Try it again (clear your cache first).