You used a very key word in all that, you are going to 'try'. Most probably if you intended to succeed and die (as opposed to hurt yourself or get help, or through anger or anything) then you would have said you were going to kill yourself tonight. So please keep trying to fight as hard as you can, use SF as much as you can, keep yourself distracted tonight, keep fighting, and try to let us and anyone else, help you.
I agree with reborn. Your gf really needs you now, and so does your baby. There is not necessarily anything wrong with your baby, which is why they are doing further tests. Do you know what they are concerned it might be?
Do you have a therapist or anyone that you can talk to? It sounds like you need some help to work through the pain you are currently in. Could you go to your doctor and explain how you feel and get some support? No one deserves to feel as bad as you are right now, so you need to try and get some positive help. It is there, you just have to find it.
My PM box is open if you want a chat.
Hang in there