I need help please

Hey I'm 18  years old.  I know i suffer from depression but have been ignoring it for long periods of time.  THe reason I'm depress is not because of death in  a family or regret though i many on both of them, but how i feel in day to day life.  The following is a description of what i have been experiencing.

Now in day to day life, I've notice some things that also that are about to worry me. Its hard for me to remember things, especially names. i can remember then, but it just takes me alot of effort to remember them. i also am forgetting information that i use to know like it was the back of my hand. It feels like i second guessing myself. My thought feel very scattered most of the time. As a result its hard for me to focus on a conversation.  I can hear what people say but its hard for me to make sense of it at times. I don't know if it's social anxiety or something, but it take me a lot of effort to be in a conversation. But when i get started, i do ok until the next day where it feels like i almost forgot how to act again. Also i've notice some changes in my vision. Sometimes when i walk out of doors or something, i see a flash of light go across. I sometimes see a flash like somebody took a picture behind me. It's also difficult to look at tile with a lot of lines in it. I keep seeing mini flashes with the small tile that sometime form shapes.  Lights are getting really bright, and i see halos around the light.  It's hard to look at object at far away, not because its blurry.  It hard to focus on it even with my glasses.  I got my glasses check about 2 weeks and they told me there was nothing wrong.

I've been having these extremely weird dream that has been getting me kinda worried. First off, i always have complete control in these kinda dream. They generally happen when I am kinda tired, and i take a nap. They usually start with me dreaming about a very realistic situation. For example, taking a shower, or playing some video game with a friend. During the dream, it feels very real, like i think its reality. Then something in my dream sparks something and my vision(in my dream) goes crazy (very shaky), and its very hard for me to move. This last about 20 seconds when i realize i was just dreaming and wake up. Sometimes my vision is still kinda shaky but i am normally very tired. So i go back to sleep, but instantly when i close my eyes, whatever i was looking, while i was awake, i have the same image in my mind. Now if i stay with my eyes closed, it will only be a matter of time before my vision goes shaky or its get hard for me to move. During these dream i normally breath, but when i start to think about my breathing, its hard to tell if i am breathing when try to breath out of my mouth. But i know i can breath out of my nose. The dreams when i go back is very surreal

All this stuff is finally getting to me, and my depression, that wasn't to bad seems to be getting worst.  I'm having suicidal thoughts more and more often.  It's to the points where its not "if" i'm gonna commit suicide, but when.  i already figure out the way i will do it. I started hurting myself again, and i cut myself for the first time yesterday.  it feels don't know anything anymore.  I just feel so alone and afraid.  My junior year of high school to my end of senior summer i was using drugs to cope with my depression.  But now anytime i smoke some weed, or drink, it just amplifies my depression times 100.  My nights usually end with me seriously contemplating suicide but usually pussying out.  Here are the follow drugs i use to take:  Weed = couple times a week Acid = 3 times X= 8 shrooms= 1 Benedryl = a lot during a 2 month period but stop DXM: 2

Please help.  i don't know how much more i can take