These blank pages are driving me crazy

I have been writing since I was thirteen, so it's been nearly ten years and I still haven't finished any of my novels. I have written seven novels and yet they all went unfinished. No matter how hard I tried to conjure up an ending all that ends up happening is I come up with another idea for a new novel. It's getting harder and harder to achieve my dream. Writing is all I have ever wanted to do it's all I have ever been good at and I feel like I am letting myself down because I can't find endings for my beginnings and middles and it's extremely frustrating. So now I am onto my eighth novel and I really love the idea I have come up with this time but this time it's different I know my beginning and I know my ending and most of the middle but there are events from the middle that I am missing and I just really need some help. It's the first time I have ever asked for help so it's my proof of absolute desperation.