Hair Help-kinda sorta wedding related (and long)

I confess I am a highlighting addict. I 'originally' had medium brown hair, and then when I was 12 the kool-aide began....then came the sun-in, and now the $150 highlights....

My hair is not bleached blonde or anything...the highlights are like a darker blonde, caramelish color....but, note that because I have highlighted it so much, there is like NO brown left whatsoever....so it almost looks like it is one color.

So, now my hair is very damaged...to the point where a lot of it falls out (is this normal?), it is dry, and the minute I walk outside, gets very frizzy...it wasn't like this until this past year or so....

My colorist has no problem highlighting my hair over and over again...and in fact, I didn't really realize it was that bad until she went on maternity leave and I asked my stylist who usually does my updos for highlights. Her response was 'Honey, god knows I can easily make a couple hundred bucks right now and highlight your hair, but I REFUSE to...it is way too weak and your hair needs to heal.'

Damn. Did I appreciate that!!!! So, what she did was 'tone' it by using a soft color to cover the roots, but then blended it in to the rest of my hair. I must admit it looked great for the first few weeks, but as soon as I got roots it started to look horrific.

Now, here is how my hair looks from root to tip:

medium brown roots followed by about 4 inches of brassyness followed by old, dry highlights...

I do not know what to do. A part of me wants to go back to my natural color and then just leave it be. My greatest concern is obviously having healthy hair for my wedding! The other part of me is scared to go back to the medium brown color because it would be a drastic difference....and FI has never seen me with dark hair, except in pictures...

I guess my question is...have any of you had this problem? What did you do? If you did go back to your natural color, did you go to a salon or do it yourself? If so, what did you use? I guess what I am thinking is since I might go back dark, it might be easy enough to do myself...

Suggestions please....before I pull my hair out!!!!
TIA girls!