Good to hear I am not the only one! Yes, my traffic has dramatically dropped by about 75% too. I assume Google changed its algorithm again. The same thing happened to me in mid-December, but I did recover within a couple of weeks. However, it hit me hard in the middle of the Christmas shopping season, so that was terrible timing. I estimate I lost about $150 in earnings. I am not as concerned this time as long as my traffic recovers again within a few weeks.
If you look closer at your stats on your hubs, I'll bet you will find your Google search traffic is seriously down. I am doing OK with Bing and Yahoo, but unfortunately, barely anyone uses those search engines. I hope your traffic improves soon!