Have a hug from me chicken
And I echo the above posts, there's some great advice there.
I've seen some dark times myself and to come through them feels so good that it's well worth fighting for.
Go to your doctor, tell him/her how you are feeling and don't be afraid to ask for help. Having a jolly good vent to someone really does help too and if there's no one in your personal life you feel you can talk to, then please do call the Samaritans. They are there to listen, they do care and they will help you.
I'm going to post a quote which I once read that I keep handy, because it's so very true-
"When we open to the truth that there is actually very little we can control other than our own reactions to circumstances, we learn to let go"
Now, don't be hard on yourself, you are only human after all
and there's always a solution, you will have brighter days