Good, I'm glad you won't have withdrawals.
"All college students drink"? Not so, sir! Consider the results in your case, where you can't get a med you need because of your drinking. If anybody gives you a hard time about not drinking, then you do have a medical excuse (as if it's anybody's business, anyway.)
As far as reasons why you did what you did or if you are bipolar, then I think those would be questions for your professionals. I certainly encourage you to tell them what happened.
I hope you will feel better soon. I also know what it's like to feel like I'm crawling out of my skin. Not a fun feeling.