[Bish0pQ]

Usually routers keep log files, I don't know if it's enabled by default though. You can try checking for the logs OR maybe try using Wireshark to detect traffic on your PC that shouldn't be there.
Than again, I would check and scan your computer first, because I still highly doubt anyone breaks into your router for a Twitter.

Also what about your neighbours? Maybe this is a thought to far, but if you had a fight with 1 of your neighbours, they could just be Wiresharking your network.
Wifi ain't that hard to crack, and with something like Wireshark running, they could have your password within hours.