A question, kerbear1973: If your friend is not getting help for the bipolar, what could you do to help her even if you were allowed to see her? If the answer is little or nothing, than perhaps you need to put the guilt away?

If calling your friend's parents to ask how your friend is doing would make a difference to you, my thought is to go ahead. They may not object if you talk to your friend. If nothing else you could use the knowledge you have gained about bipolar to urge them to get your friend into treatment.

What seems pertinent to me is that you do not allow your friend's misfortune to vitiate the work you have done to make a better life for yourself.

Good luck.