Just a guess, but the servers the Tribler team uses are down. They are the ones that handle most of the downloads at the moment (since the amount of exit nodes are very limited) and then everything goes to a halt if no other person with Tribler is seeding the exact torrents you are trying to download. Something similar happened last Christmas (or the one before that)
For now, i don't know if there's much to do apart from possibly making yourself an exit node to help others. Though VPN is recommended since you'll be doing other peoples traffic, and you don't really know what people are downloading with you as a middle man.
Edit: Or more obviously, using no anonymity will make things fast as any other torrent program, but no anonymity obviously.