Um, anyone here uses twitter? I could really use some help

I was on Minecraft Planet looking at texture packs, someone mentioned Jappa, a guy that make texture packs. I don't know if it actually happened or coincidence(I hope it's just coincidence), but when I clicked into his twitter, things instantly got fucked up. I got automatically logged out, and I can't go back in no matter what.
It keeps telling me something is wrong, but it won't tell me what's wrong. Sometime later, I tried again, now it told me there's "unusual login activities" on my account. Restarting my computer and WIFI is ineffective.
And it got even worse, the screen with the "sign in" and "login" button got all glitched and screwed up.
Now I'm getting shocked, did my account got hacked or what? Or it's just a random error that happened to Twitter once a while? If you used Twitter and you had similar incident, please explain this situation, it really got me frustrated and nervous