No panic attacks can not harm you, I know because I have had them for years.
Go to the clinic at your college to see someone about this, regardless of what your teacher said.
Make sure you get outside of the house everyday, for at least an hour.
It is easy to become so afraid of these attacks that you end up doing nothing not even leaving your house.
Be good to yourself and take care of this as soon as you can.
To calm down, take slow deep breaths, so that your lower belly rises..breath in slowly to the count of 4 and breath out slowly to the count of 4, do this until you feel calm again.
This will trick your brain into thinking that your body is calm.