I would try to weigh up whether you honestly think you will act upon these thoughts, you don't have to tell us on here, but you need to decide on this yourself.
If you don't think you will act on these desires, but you instead are feeling "I feel so utterly despairingly distressed that I need something to take this pain away " - that's a little more hopeful. Because, in time, you can find these things to take the unbearable pain you're in away. It won't be overnight, it'll be gradual. Feeling very depressed but not actively suicidal will be an improvement.
If you tell your GP you feel suicidal, yes, it will prompt concern for your welfare and the welfare of any dependents- they have to act responsibly, it's their moral and legal duty. But that's better for you and your family than you being dead .
If you feel you will not act on your thoughts, please see your GP to get you signposted to the right services who can get you on your journey to better mental health. Anti depressants would be a good place to start. Sleep is essential. You must put your very basic needs first right now.
If you really think you risk acting on your suicidal thoughts, bypass GP and get to A&E (it is an emergency) where you can access immediate help as you need and deserve.
How you feel is horrific. I'm so sorry you're feeling those feelings.
Please take care of your lovely self. You have as much right to be on this planet as every fucker else! Never forget that x