I very much agree with the bolded, and for someone like yourself with a complex, chronic illness, it would be foolhardy to suggest you should ignore the benefits of drug therapies - whatever they may be. Insomnia and long-term sleep deprivation is a serious a symptom as any other and there's no reason it shouldn't be relieved. I think having a doctor like you mentioned, who is managing the entirety of your condition is very important and personally, I'd not give a fig about what anyone here thinks as long as you are comfortable with his treatment plan.
Now back to your original question, sometimes medication is NOT the answer, and I think you knew that in this case. I'm no expert on mental health, or the meds that treat it, but I know that the drugs for depression/anxiety are different than tranquilizers, and that "numbing out" is not what you really want to do here.
I offer this as kindly as possible (it's so hard to read "tone" in a post).
You're not facing a loss, even though it might feel that way;
you're facing a change in the seasons of life and a permanent one. Pithy as it may sound, the only way out is through. "Sad momma" isn't a pathology, painful as it may be. Remember back through her childhood - I'm sure there were many other instances that caused you heartache because that's what sacrificial love does, but it's the right order of things and it's beautiful. You've raised a healthy, smart, competent girl with forward momentum - that was the goal, right? Great job, Mom!
Given that the alternative is to hold her back in the interest of your own comfort, you and I both know you'd never let that happen.
Take this time to start transitioning yourself into a new normal. With a redistribution of your time and resources you can put new focus on other relationships (marriage, extended family and friends) in both giving and taking. It's also time to reexamine your own identity aside from being a parent. YOU have a future too, not just your daughter. Anyway...all of these things I'm saying might seem cliche, and intellectually you already know them all. You are a strong, resilient person who has been through a lot, but you've also got people who love you to come alongside, as well as my full confidence.