chasing unfortunately the first few weeks on antidepressants can actually be a time when you are more at risk of suicide. Having been suicidal myself in the past, I am concerned by what you are saying. If the thoughts are fleeting, that is one thing, but if you get to the point where you are planning, or dwelling, fantasising as it were, then please talk to someone in real life - even go to A&E or phone the Samaritans, police etc. actually, I think phoning the Samaritans now wouldn't hurt one bit - a chance to vent, sort your thoughts etc.
The Friday before last the thought of jumping under a lorry seemed like a really good idea. I had taken DD1 to school and was walking home. The younger ones were with Daddy, and for a moment it seemed like a solution to my dreadful tiredness. Thankfully I did not act on it, and soon felt a lot better. It was the day after that dreadful incident at the railway station when the depressed mum killed herself and her boy. At the time I felt quite jealous of her, and understood why she would do such a thing. Just a few days later and I see it as the tragedy it was. Such a waste.
After DD1 was born I had post natal depression, but did not seek help. I struggled with serious thoughts of killing myself, and also taking her with me I am sad to say, as at the time I thought we would both be better off. I was extremely lucky to have got through that, seeking help when DD was 8 months old. Please do not suffer as I did - get help. Do not be afraid to ask for help.
You have not made a mess of your life, and there will be a way through if you give yourself a chance. It can be very hard to see this when you are in the midst of depression. We see a beautiful brave young lady with a delightful little boy, who has a life full of potential ahead of her.