Hey OP, godzilla of a response coming up here,
Like many others who've contributed to your post, I've been where you are. I've dealt with depression's bitch face for the past three years but it's worsened as of the last year. Around May, I met a guy. He was amazing. Funny, smart and cute. Needless to say, I fell in love with him and began living in accordance to what he thought and how he interacted with me. Back then, I'd literally thought he saved me. He could breathe and I'd come running, and I still cringe reflecting about all of the stupid, lovestruck things I said to him. But hey ho, he's gone now and back when it happened, the pain was quite literally, unbearable.
Hours were taken off my already damaged sleep pattern and I'd find myself having fits of crying beyond anything I'd ever experienced. The moment I realised he was seeing someone else is something I'll remember for a long time coming. The fact that he was now seeing someone both older, more beautiful and closer to him than me added insult to injury, so to speak. It sounds petty to get off my chest, but I found that the split brought out the absolute worst in me. So it sucked majorly for a while, to put it lightly.
But I soon realised that my attachment to him was born not of love, but desparation. I'd been hopeless for so long that he was a beacon of hope. What else could I do but cling on? We all self medicate in some way, some through drugs/alcohol and others through romance. They are equally destructive to a depressed person. The rub is that depression makes you desperate and yearning for love, but also makes it so that love is almost impossible to attain. You are worth so much more than what another girl thinks of you, the same way I am worth more than what he thinks of me. It took a while to hammer that in, but I think that along with a good dose of Prozac is helping it settle. The key flag in your post was the use of the word 'void.' There's something missing in your life that you believe women can fill. They do temporarily, but when they leave, it only worsens your situation. So here's what I'm doing- staying single. Work through the issues with a therapist, beat the absolute living shit out of depression and become stable enough to maintain a healthy relationship.
TL;DR- You are super rad without the approval of girls. There's something missing within you and until you find that, nothing can fill the void. Well, apart from fries and ice cream. Because food.