I think she's doing well. Her current diet has the essential nutrients and vitamins she needs, right?  Its very understandable that you to worry a bit because her menu is totally different from what we know as dinner.  But there's essentially nothing wrong with it. It will change soon enough. You'll be surprised and plausibly delighted how your baby will explore other foods and avert from the previous faves.  She eats a lot eh? Awesome, and lucky you!  But yeah, you can always introduce other foods like meat and vegies.  She may not know what great stuff she's missing.  ;)

Hi Raina,
Have you tried adding other things to her grilled cheese sandwich?  Katelyn had a phase where all she wanted was mini croissants and cheese for dinner so I would add cucumber and chicken to it and b/c it was in the croissant she would eat it.  If I gave her the chicken separately she wouldn't touch it.  You can try cutting really thin slices of chicken and add that to the grilled cheese and she if she likes it.

Keep in mind that toddlers eat less than babies b/c they are not growing as much as when they were babies. She might have one day where she eats a lot and then other days when it seems she's not eating anything at all. Just try to follow her cues and give her a variety of foods to try.  Also, if it helps, think about her intake in terms of what she had over the week v.s. on a day to day basis. If she had a balanced week with a good variety then I would just let her have her comfort food for dinner :-) 

Did you check with her pediatrician?

long time no see give the little cutie pie a hug for me :-) 
-Claire