Tweets not visible to other users in threads. Please help.

So I've been told by users that they can't see my tweets when I reply to a thread. This is the conversation that I had from the user that noticed it:

User A: [replying to User B] Oh sorry, I thought you were replying to (other user, uninvolved)
User B: Can you see the post I was replying to? I can only see it through my notifications.
Me: Wait really? I probably turned on some setting unintentionally.
User B: Yeah. I'm struggling to see your posts without clicking your profile. You're not even showing up in my notificatins.

Clearly both users could not see my tweets, and were confused as to why. The Twitter support DM service was down, and has been ever since, so I can't use that. So I sent a form to the online service, and I got a reply saying that I should change my password, because something might be affecting my account.

So I did that, and it didn't resolve my problem at all.

I honestly don't know if it's a technical issue or if I turned on some setting by accident that I can't find in my numerous searches of settings. Does anybody know how to fix this?