Hi AphexSam - if you haven't already, you should really call a doctor or even the emergency services as soon as possible about this. It's worrying that you say you lost so much blood and (when you posted, at least), felt faint. I hope you are physically okay now, but in any case, I strongly encourage you to get medical attention immediately, because it sounds like you are very depressed and need medical intervention, just like any person suffering from any illness would. I myself used to have a self-mutilation problem due to depression and you really can stop cutting yourself and feel much, much better if you see a doctor - general practicioner, psychiatrist, etc. - and tell them about the cutting and feelings of self-loathing. In my case, finding the right medicine (after trying several ineffective ones) really made a positive difference.
If you're hesistant to call medical services, please, for your own health, tell a family member, neighbor, or advisor - whoever you can talk to now and who you feel okay talking to - what happened and ask if they will call for you. Write exactly what you posted in a note and hand it to the person if you don't know what to say, say it verbatim. Don't worry about causing a scene or upsetting people - you absolutely need medical help. Just be sure that a call is made soon. I know you feel very bad now, but your life and well-being are precious and it would be a terrible tragedy if your depression were allowed to continue untreated.
That goes for anyone who is depressed and/or feel they are danger to themselves. I hope this note has not come across as harsh or patronizing, and I'm sorry it's long-winded, but as someone who has been in the same situation, I promise you it can get better but you absolutely must get help! Your life is sacred - I mean that in the all-encompassing sense, in whatever sense it is meaningful to you (secular or spiritual).
PM me if you want or need to! I really care and want you to stop suffering soon and feel better.