Aftershocks!! No one but dumb people can accurately forecast when they will occur, so I would say that you should be somewhat concerned for the next three days at least..... but as a consolation .... aftershocks are USUALLY much smaller than the primary quake you just experienced.
Another comment about ones feeling before, during, and after a sizeable quake.
Waiting for an aftershock to occur is a pretty bad feeling and on many occasions I've noticed that for some unknown reason, people start getting funny and often laugh for no reason at all. I've heard comments from smarter people than me (there are a couple) that fear of the unknown causes people to laugh when nothing funny is happening.
And during the actual quake ... vertigo, helplessness and sometimes panic are very common. And panic is probably the most dangerous if you are in a crowded place such as a theater, department store, or even while shopping for groceries.
I'd avoid large, crowded areas until the area settles down.
ANd then after the ground stops shaking, you sort of wait in fear of the next shaking period, so expect to be somewhat uncomfortable for the next few days.
You mentioned that your chimney was shaking. If it's a brick chimney , it'll most likely be the first part of the structure that will collapse. Nowadays brick chimneys or structures over a certain height are forbidden.
I'm a bit surprised that this quake ocurred on the east coast though as I thought that they were relatively uncommon back there ... but someone once told me that the largest recorded earthquake within the USA actually did occur back there somewhere.
Here are some photographs of things not to do in earthquake territory
