Why I fight this. Why I have survived: Today's Thoughts

I fight this because I feel like I have to, not because I want to. I want nothing more than to just give up and let the end come. The demons in my head and dark, dull-grayish vale that depression seems to put over everything seems endless. It feels like there's no hope, no end to depression, no light at the end of the tunnel and the longer I endure it the more it twists me mind. The more it warps my mind and twists my thoughts. The more it screws with my psyche until I can't even think straight.
Although I know a lot of the horrid thoughts, images and voices that whisper in my head are malicious lies but sometimes those lies, repeated so often over such a long period of time burrow too deep and cannot easily be removed. They become a part of my every day life, become a part of the regular routine, firmly embedded so strongly and blending in so seamlessly that I don't even notice them anymore until they start effecting my life again.
Thankfully there are things I can do to improve my moods and help my mind function as close to normal as possible. For the time being I'm on meds that, thank god are starting to kick in even faster than usual. It's been only a few days and finally the dark, heavy, scary and malicious fog of depression seems to be lifting. My mind is starting to function normally again for the time being but these drugs can't fix me. They can only help. I can't even fix me. There's no magic anti-malware for the brain to weed out all these now subconscious "bugs" that depression and loneliness has planted in my head.
It's been 4 days since I talked to the girl I was dating and I am so sorely tempted to try and call her that I came dangerously close to it earlier, but now that my mind is finally working semi-normally again (ironically, I can partially thank some illicit drugs as well for this), I've been doing some serious thinking:
 
WARNING!: As usual, this journal is going to be quite long-winded. I realize some people (who are undoubtedly not reading these anyways) want to just respond to the meat of my journal, just write your response and stop reading here. From this point on it's pure speculation based of past experiences and things I've learned.
 
 
Ok, that's taken care of. So, here's the reason why I've chose against my better judgement to let my guard down and actually take to heart what this girl has said to me. Its because it actually did seem genuine. The way she looked at me, kissed me, held me, the tone in her voice, everything seemed real for the first time in my life.
However, I have been tricked in the past! Once upon a time, there was a woman who could look me square in the face and lie through her teeth that she loved me. That she wanted me. That she really truly does want to have a serious relationship with me. She lied, cheated, and although her intentions were admittedly somewhat clear and obvious I was stupidly blinded by my own feelings for her. I should have known better. I should have listened to my gut (and several good friends who all suspected what she was doing.. Sorry Jo. We both know who I'm talking about here).
I had every reason in the world to disbelieve this woman. I should have turned away, gone with the advice of many of my friends and simply ended it there and then. Her intentions were anything but good! Deep down, even I knew she was lying to me. How could I not, she practically spelled it out to me several times and once flat out admitted she was lying. Why the hell did I fall for it?
This time is different. I am skeptical. I do still sort of have my guard up. I haven't given in completely to her seductively good looks and incredibly body, but this time I can't for the life of me find any motive for the things she's said to have been a lie. There's nothing for her to gain, no prize to wrapping me around her finger and manipulating me. No ultimate goal, no stupidly obvious malicious intentions. Her feelings really do seem genuine and up until about 6 days ago, her optimism and enthusiasm for our relationship and the way she looked at me and seemed to completely relax and open up made her feelings seem real this time.
Like I said, even with all these cues it is incredibly hard for me to believe this is for real because of far too many negative past experiences. No one has ever looked into my eyes like that, said she loves me and truly meant it before. With the woman mentioned earlier (the one who was lying about it), I could have so easily seen through her lies simply by the way she kissed me. How she never really seemed to say that unless she actually had some end goal in mind. But with this new girl, there was none of that. The way she held me was so much warmer, closer, her kisses deeper and more magical. There truly did seem to be more heart and soul in it.
So why? Why suddenly this distance? It's not like she's necessarily colder, just more distant. Often not responding to texts until hours later if at all. Whats going on? What am I supposed to do? I stopped txting/talking to her four days ago simply because all the enthusiasm and optimism seemed suddenly gone! The two biggest reasons I was pursuing her at all, rather than giving up are no longer there and it scares me because instead of keeping my distance, keeping my guard up and keeping my own feelings in check, I've actually relaxed and let myself start to have feelings for her. Feelings that seemed mutual...