Oh, I am sorry to hear this!
Yes, if you were released, then you can rest assured that everything is okay with you in a physical sense.
Were you not given an assesment by the attending, or any release papers? Any medication or therapy referrals?
Try to remember what the doctor on duty told you...I know it is hard to retain anything while you are panicking, but follow any advice that you can remember.
Try some deep breathing for now and progressively relax your muscles from your head to your feet. Repeat a postive mantra such as 'I am okay now.' over in your head...and try and get some rest.
Let us know how you are doing soon.
S.C.