Well, it sounds like there's a cluster of symptoms that are happening. They may be interconnected or they may be separate. Why don't we deal with them separately and go from there:
1) You mentioned fear of abandonment as being a key issue for you. This is a hallmark of Borderline Personality Disorder, as are the suicidal tendencies and attempts. Borderline PD can be very difficult and is usually caused by some childhood trauma or a difficult relationship with your primary caretaker. Impulsivity and depersonalization also go along with Borderline PD.
2) Auditory and visual hallucinations - these are typically linked to psychotic disorders, but can be linked to severe depression, drug abuse, or mania. What do you think set off the hallucinations?
3) The extreme worry about illness is probably linked to anxiety. It's not a panic disorder, per se, but it sounds like it comes close sometimes. Debilitating anxiety often leads to depression, which will occasionally lead to suicidality if it gets bad enough to where you feel you can't control it.
Here are my questions for you: have you ever been diagnosed with borderline personality disorder before?
Do you experience the hallucinations anymore?
Alright, well there is a slightly complicated picture here, but I think we can parse it out a bit - thank you for all the details, by the way - it helps immensely!
I understand what you're saying about that particular symptom of Borderline. It doesn't seem to fit with you, however, many of the other symptoms do. And, you don't need to meet all the criteria to be diagnosed with the disorder. That said, I think you have a pretty balanced view of what you are and aren't doing in your relationships. That's a great start and could probably be expanded upon.
And, as you mentioned above (about the abandonment by the boyfriend/death of grandpa), it sounds like the variable that precedes the hallucinations is also abandonment. Thus, I'm beginning to think that everything is interrelated and probably comes back to the Borderline again. In my opinion, this is good news. This indicates that no, you're not suddenly going crazy - it's all part of the same thing.
But, it also means that finding treatment for the Borderline with someone who is very competent would be really important for you. Ideally it would be great for you to find someone who understands that everything goes hand in hand and doesn't try to treat everything separately.
Have you ever tried Dialectical Behavior Therapy with an adjunct medication like Seroquel?
Yes, of course that makes sense. You are at an impasse where you know that something needs to change, but change is always frightening.
If you like your therapist and you feel like she's helping you then I would stick with her. However, if you feel like she's more of a friend than someone who is helping you with your issues, you may want to reconsider at some point in the future.
Regardless, a new medication could really do wonders I think. I know you're afraid of the Seroquel - how do you feel about SSRIs like Prozac? I know you mentioned that you'd tried some before, but I ask because a higher dose of an SSRI can help a lot with anxiety and doesn't have the side effect profile of Seroquel.
You know, I've always liked Prozac. It seems to be a really clean antidepressant - I don't hear of that many side effects. It helps with anxiety too (as the anxiety and depression usually go hand in hand). It might be worth a shot to see if bringing up your mood will help with the other symptoms. Using Prozac in connection with an anxiolytic like klonopin or ativan is an awesome combination for anxiety disorders like OCD. I've seen it totally turn people's lives around.
I have faith that what you're experiencing now is just some heavy anxiety and nothing more than that & that the correct meds would knock it out. Additionally, Prozac can be known to cause a bit of a "brain fog" at the beginning (first 2 weeks or so) - it generally wears off. Also, that would've been much more pronounced in adolescence (the concentration thing you were talking about).