What can I do for the gap between my top and bottom front teeth?

I am 20 years old, and recently ( within the last year and a half) my jaw has moved. I had braces at around age 14 to straighten, my front top and bottom teeth always touched, like normal. They no longer touch, the ortho I went to said the gap is about 4mm. I have been told I have TMJ and I grind my teeth. I wore a thick mouth guard for about 2-3 years, one ortho I went to, said because it was so think it could play apart in the gap. No one has idea why this gap has occurred. I currently have cleats on the back of my top four front teeth, honestly doing nothing. Most ortho's only suggestion is jaw surgery, but that just sounds so outrageous to be the only option, since my teeth have always touched until recently. I would like to hear what other options there, and perhaps if something like this has been heard of before? I've looked at braces and tongue online, would that help my problem? Side effect wise, I hate the appearance of my smile, I use to love smiling but I no longer do. Besides looks. It is extremely difficult to eat certain foods, such a lettuce or sandwiches. I also have developed lisp, which also extremely annoying.