You forgot possibility #5: There really are problems in your relationship.
It's easy for us to agree say that it's her issues, but we only have your side of the story. Maybe you really do destroy things, even though you say you don't. Maybe you do have habits or behaviors that are detrimental to the relationship. I'm not saying that you are 100% to blame, but without hearing more, I'm not convinced that she is either.
You've been together for two years. I think if she was bipolar or "demented", this would have come up before now. Have you guys had fights like this before? You really can't think of anything that could have brought all this on? Something earlier in the day?
You said you love her very much and you don't really believe that she wants to break up. I'm guessing you don't either. The best way to handle all of this is to sit down and talk CALMLY about things. Tell her that you don't want to fight and if she is having issues with you, that you want her to tell you about them without you guys fighting. The only way this is going to work is if you both make concessions about things you are both doing that are causing problems. Blaming her 100% is not going to work. After all, if she were really that destructive to your relationship, why would you want to continue with her anyway? You know she at least made some vaguely valid points. Stay calm, even if she gets angry. Don't throw things in her face (don't bring up the soap operas) or blame her for all of it. Just try to get to the reason why all this happened and try to fix it.
Please let us know how things work out. Good luck.
Oh, by the way: As for the needing total darkness to sleep, have you tried a sleep mask? My boyfriend has the same issue and it works for him. He had to try three different kinds before he found one that fit right (at the drugstore in the eye section). Just thought I'd throw that in there.