From couple of weeks i am having suicidal thoughts. Only thing which is holding me back is my 4 year old son. I don't think it will hold me any longer.
Today it got worst.
I just want my suffering to end.
Well for starters I want to thank you for letting others know how you're feeling because, I don't know about any of you, I've always felt a lot better when I've had a chance to air my grievances.
I'd encourage you to seek guidance from Allah (swt), take comfort in your family as well as seeking professional assistance in combating the maladies and suffering you're currently facing.
Bad relationship and then I lost my soul friend in bike accident. He just got engaged.
This is an edit because you literally responded just before I posted my initial response.
Sorry to hear about your friend. A cousin of mine was also seriously injured in a motorcycle accident years back but by the grace of Allah (swt) he was saved.
It's not surprising you're feeling like this because you lost someone important to you and important human relationships are linked with elevated dopamine (neurotransmitter associated with pleasure) and serotonin (mood regulator) levels in the brain. Once you lost your friend you also went on a withdrawal of those important neurotransmitters which is going to cause you become anxious and depressed.
I think something that could really help you, anyone for that matter, is getting regular exercise which is also associated with elevated serotonin and dopamine levels in the brain.
Furthermore, a lack of sunlight, or rather Vitamin D, has been linked to depression.
Nature also has a very calming affect on our minds so if you could get out of the city and maybe go hiking every weekend perhaps make it a family outing or go with good friends that could also help.
One thing I also tell others is that if you can't live for yourself then live for others. Do charity work, help the less fortunate and I think getting involved with others towards a shared goal particularly one as noble as helping the needy can bring new purpose to your life and give you goals to strive towards.