I occasionally get contacted by people who appear to have a mix of what appears to be real insights of some kind and also real mental illness that is clearly interfering with their function. How best to help them is not a straightforward. 

While I have an MD and routinely deal with mental illness in the emergency department, I am not a licensed psychiatrist or psychologist, and my expertise is generally in immediate crisis stabilization in the emergency department and referral elsewhere and/or inpatient hospitalization. Further, the long-distance format of communication and the lack of time to really get to know the person who is experiencing these complexities severely limit the real help that I can personally offer.

Possible places to try to turn for resources: 

1) Your local mental health clinics, and, if you are in crisis, your local emergency department. While they are unlikely to have dual expertise in psychiatry and also meditation side effects, getting stable is the first step, and that is something they do know about, and then sorting out what meditation component might be part of all of it may be attempted when stability and a lack of psychosis or severe depression has been established. 

2) The Spiritual Emergency Network and the Spiritual Emergency Service may be able to refer you to local resources.  The Spiritual Emergency Resource Center may also be helpful.

3) Cheetah House has some information and resources for those experiencing difficult meditation side effects.  It is run by Dr Willoughby Britton, but unfortunately she is generally quite busy with her research and will generally refer people elsewhere.

4) I am told that the Institute of Noetic Sciences has some resources for helping people also: consider contacting them once immediate stability has been established. 

Realize that sorting out what is what is not easy.

Other general advice:

1) If you have recently stopped taking any antipsychotic, mood-stabilizing, anti-depressant or other bipolar medications without the advice of a physician: get back on them and call your prescribing doctor or their on-call partner immediately.

2) Stop doing any intensive meditation practice.

3) If you have a qualified meditation teacher: also let them know what is going on. 

4) Avoid any visualization and mantra-based meditation practices.

5) Seek the support of understanding friends and/or family if you are luck enough to have them.