Star Wars: The Old Republic yesterday, you may very well have been hit with some lag and disconnections. The good news is that it's not a problem with your ISP; the bad news is that it appears to be yet another installment in the ongoing saga of irritating twits with nothing better to do than try to damage servers. Yes, it looks like this was another DDoS attack.
Community manager Eric Musco's last update on Sunday night indicates that most of the issues should be resolved now, but it's possible that players may still experience intermittent connection difficulties. The representatives from BioWare have not officially stated that it was a DDoS attack, but it lines up perfectly with a DDoS attack made against Electronic Arts servers, leading to the accepted conclusion.
[Thanks to Leiloni for the tip!]