Arghhhhh 
Your heart is breaking. It hurts… it hurts.
You’re right that booze won’t help (obviously). There is absolutely no way it will help anything.
Also - and this is harder to see now but it is there - a relationship doesn’t fill the void either. As you said,
The relationship that needs work now is your relationship with yourself. A relationship is about walking through life - that’s the whole thing right? A relationship is “this is me walking through life’s emotional challenges with ____ and facing the challenges, not running away or escaping” (because facing those challenges and learning from them is what builds a strong relationship (not a dependency relationship; a strong relationship is two generally healthy independent people who choose to grow a life together, not because they have to but because they want to) - so the fundamental relationship, the one that is the foundation for every other relationship in your life, is “this is me walking through life’s emotional challenges with myself and facing the challenges, not running away or escaping”.
You feel like everything’s falling apart but what’s actually happening is you’re cleaning up and getting your house in order inside yourself. You’re at the very beginning of your relationship with yourself. You’ve never done this before, so there are years and years of repressed emotions and thoughts and memories that will burst out. Like you said,
Totally normal. It will be a lot, as all that repressed stuff comes up, but the only way out is through. You have to do this, and seek out all the healthy support you can get, to find your path. Reach out here on Talking Sober, join a recovery group (in person or online, there’s groups basically 24 hrs a day) where you can find people who understand (like these Resources for our recovery and www.InTheRooms.com and Online meeting resources and if you search “marathon AA meeting” there’s lots of links to 24 hr meetings), find the support so you’re not alone.
You have to spend time with yourself and live life without numbing or escaping. It’s ok to grieve your boyfriend leaving. It is heartbreaking - it is. And even though it’s hard to say and hard to hear, this happens. (I know it’s hard.) But you have to reach out to healthy supports (like here and at the links above) and find people who will listen, and then start processing your feelings and thoughts, with their mentorship and support. It will get better. Stick with it and it will get better.
We’re here for you. You are not alone. You matter, and you belong.