Depression that never seems to end.?

I don't know what to do with myself anymore. I am not exaggerating when I say that I feel sad almost every hour of everyday. I have lost all my inspiration. It makes me sad because I use to know myself so well, but now I am not even sure who I really am anymore. I feel lost, and constantly my mind is running thoughts and memories, It is like I cant control it anymore. Its overwhelming and controls my everyday life. My sleeping schedule is horrible..it changes, but not frequently. Because of my depression, I feel as if I can't sleep...I stay awake until what seriously feels as if I am passing out. It is very painful for me since my sciatic nerve is messed up, so it tends to act up more at night, as well as my restless leg syndrome and asthma. I work full time so it makes working a drag. The past 3 months/recently I believe I cry about 4 times a week waking up, at work and before bed. I thought that it might be from my ovarian cyst but I have had them for almost 6 years and have never dealt with depression as bad as this. Since I was a child, I have dealt with depression, but have never been diagnosed due to money issues. I do believe that the depression in my past had a lot to do with the environment I grew up in and the constant everyday battles I faced with dealing with my parents who where drug users, argued everyday and neglected me at least until the age of 13 when my parents made more money(my happiness was "bought") I also used to cut myself. I fought myself so many times to try and ignore the thoughts. When I tell my parents about this, they don't seem to take me seriously. My mother puts her friends before me, and my father is extremely obsessed with my mothers absences and how it effects his life, to the point to where my problems don't exist at all. I am 19 years old...I still live in this house and giving money to my parents is hard to do, especially trying to improve and take care of myself as well. Everyday I suffer because of my emotions. I feel so miserable and almost so much so to a point of insanity. I am scared because I started to notice that I talk to myself out loud and really don't notice it until I kinda catch myself I guess. Throughout the day I feel the urge to cry several times, but mostly I end up reaching a point of what feels like major anxiety. I can feel my chest tighten, and this horrible butterfly in my stomach sensation...but not the good kind. I get really dizzy and I get migraines at least a couple times a day. I am also very insecure because of all of this. When someone looks at me on the street I tend to think they are looking at me because there is something wrong about my appearance, not that they are "checking me out." And last year, two people I got very close too betrayed me and hurt me so badly that it has now caused me some serious social anxiety outside of work. I shake a lot and it almost takes anything negative to set me off emotionally... I can't let things go....when I am upset I stay that way over the issue for a very long time...to the point of constantly beating myself up mentally...of how stupid I am or pathetic. And when I cry, sometimes I cant stop... and at times causes me to have panic attacks. I cant be around people to long other wise I feel suffocated...like I need to be alone. The thoughts in my head wont shut up....and I cant handle it...I get to high levels of stress over this, to where I throw almost a child-like tantrum, but only in private. And even when I experience laughter and smile I still feel sadness within me...its like it is eating at my insides. It makes me feel sick and want to throw up. Also I do believe this is caused, not only from home life and personal, self loafing issues, but from my complicated love life. I met someone who I am now still involved with on and off romantically about 4 years ago. He lives about 8 hours from me though. He changed my life for the better at first but over time became verbally abusive. He tells me I am pathetic and stupid and a *****, etc. when he gets mad at me and tells me how everything is my fault, but then other times he is the sweetest guy in the world and very loving. I tried moving on once, went on a date with a friend...we ended up kissing once. I told him about it recently and he called me a cheater and that I should feel ashamed (even though we are not together now and weren't when I went on that date). Ever since I have felt incredibly guilty and more depressed then before. I think about ending it all sometimes. I feel worthless. And it makes me incredibly tense..I can't even clean my room...to the point of getting carpet beetles (I look like a hoarder)...I panic when people go in my room because my room is like a window to my soul, metaphorically. I don't like people seeing my pain. I have so much potential to be someone in this world...but I always feel depressed..like it will never end. Please, what should I do? Help me?