Hey there. I know exactly how you feel. I have been in your shoes, my son moved out at the end of August. Similar situation - heavy pot use, alcohol use, was attending college primarily to party and he moved out when we decided we would no longer finance his school (ie: partying) lifestyle. He too said horrible things to H and me as parting shots. 2 months later and they still hurt. He is back at school -- supposedly paying his own tuition and going to class and supporting himself with a min wage job. I don't buy it for a second, but it's not my problem.
Please try to get some sleep. My husband finally took me by the hand, gave me a tylenol pm, turned down the bed and said "go to sleep". I can't say the the sleep necessarily helped, but at least it turned off my mind for the 10 hours I was out.
Please try to stay busy. I used my difficult child's former allowance to pay for manicures and shoes. A little retail therapy never hurt anyone especially if you use the $ your were spending on your son.
I wish I could tell you things are better now. But my difficult child is stubborn - true of most young men. While I know we did the right things - AS DID YOU - I was caught off guard by how long he has managed to stay away. Things have very slightly thawed between us - but only VERY slightly and only because I have pursued communication with him. There is no easy reconciliation and please realize that it's unlikely that he will come to his senses soon. And resist the urge to get him back at any cost - it will backfire on both of you.
This board has been my lifeline and has kept my sanity in check. Sometimes only barely in check. So when your mind is going around and around in circles - visit us here. Write it out - read the responses and some of the fog will clear. Not all of it, but some of it. Most importantly, you will know that YOU are not crazy. At least for me, my mind kept going in circles and circles and I second guessed every single thing I did over his lifetime - especially the events immediately leading up to his departure. And I started blaming myself. Lucky for me, the wonderful parents on this board snapped me out of it!
DO NOT BUY INTO THE SELF BLAME. On this board, I learned that by pacifying him/placating the situation, I handed him the control. A light bulb went off - AHA! You cannot change him. He has to change himself. As tempting as it may be to take it all back and look the other way - that won't change his behavior. He'd just be doing it all with your unspoken approval and your funds. My h reminded me of that more than once. If we'd looked the other way and paid his tuition - he'd likely be partying more not less. And the worry would still be there. Nothing would change except the balance in our bank account.
You are not lost. You just feel lost because your world is upside down. It will get better. Your heart will ache, but it will get less acute. One day you will realize that you didn't cry yesterday. And then the day will be a week without tears (still waiting for that) but it WILL happen. It's a horrible thiing to get used to - but you will. Life will go on...and we are here to extend a hand and a hug when you need it.
Take good care of yourself - pm me anytime. {{{HUGS}}}