On the brink of giving up

I’m 25 years old and have suffered from severe depression and anxiety since I was 14. Medication and therapy have been of little assistance. I’ve had a very difficult social life due to this problem making it difficult to form friendships and impossible to find a romantic relationship the latter of which has devastated me more than anything. I recently spent a day with a girl I connected with more than anyone I have ever met, agreed to stay in contact with her and within a few days she completely cut off all contact with me without explanation. This is the only time in my entire life I have ever met anyone like this and almost immediately she wants nothing to do with me. I just want to find someone to be with so I can have that emotional connection that I feel is a necessary part of life but because of my social awkwardness and emotional instability this has been impossible. I’ve attempted suicide before on impulse but this time around I’m considering it on a very thought out basis. I just cannot seem to form a life in which I will be happy. I can understand not committing suicide on the basis of it would hurt my family and friends but I am being mentally tortured everyday. I can’t bear this nightmare of loneliness much longer. If anyone has some words of wisdom it would be greatly appreciated.