You aren't suppose to lose anything you bought or unlocked (inventory expansions, cargo bays, legacy unlocks, etc).
I think you are knocked down to two quickbars.
You won't get those cartel coins unless you resub by 12/20.
You can still use all your gear you currently have, but if you gain new epics you'll have to buy the unlock for those.
What happened to your guild depends on a lot of variables that it really wouldn't be worth the time to delve into. You should log on and check on that one.